All The , 4, -continued fractions of the first, 200, primes By Shalosh B. Ekhad The square-roots of the following primes do not seem to have an umtimately \ periodic,, 4, -continued fraction judging by the first, 2000, terms [19, 43, 67, 71, 73, 97, 109, 113, 127, 139, 149, 151, 157, 163, 179, 191, 211, 239, 241, 251, 271, 277, 307, 337, 349, 379, 389, 409, 419, 421, 431, 433, 467, 479, 487, 491, 503, 509, 521, 523, 541, 569, 571, 587, 599, 601, 613, 617, 619, 631, 641, 643, 661, 673, 691, 709, 719, 739, 743, 751, 757, 787, 809, 811, 821, 823, 827, 829, 859, 863, 877, 883, 887, 907, 911, 919, 937, 947, 953, 967, 971, 991, 1009, 1019, 1021, 1031, 1039, 1051, 1061, 1069, 1109, 1123, 1151, 1171, 1181, 1187, 1193, 1201, 1217] Among those that do, the largest period is the square-root of, 1033, whose period is, 50 Here are all the successful ones 2, : , [[1, 9], [6, 44, 6, 10]] 3, : , [[1, 5], [8, 6]] 5, : , [[2], [16, 4]] 7, : , [[2], [6, 20, 6, 4]] 11, : , [[3], [12, 6]] 13, : , [[3], [6]] 17, : , [[4], [32, 8]] 19, : , FAIL 23, : , [[4], [5, 152, 5, 8]] 29, : , [[5], [10]] 31, : , [[5], [7, 88, 7, 10]] 37, : , [[6], [48, 12]] 41, : , [[6], [9, 4, 11, 4, 9, 12]] 43, : , FAIL 47, : , [[6], [4, 5, 4, 12]] 53, : , [[7], [14]] 59, : , [[7], [5, 4, 6, 4, 5, 14]] 61, : , [[7], [4, 4, 14]] 67, : , FAIL 71, : , FAIL 73, : , FAIL 79, : , [[8], [4, 7, 4, 16]] 83, : , [[9], [36, 18]] 89, : , [[9], [9, 18]] 97, : , FAIL 101, : , [[10], [80, 20]] 103, : , [[10], [26, 4, 6, 9, 6, 4, 26, 20]] 107, : , [[10], [11, 6, 10, 82, 10, 6, 11, 20]] 109, : , FAIL 113, : , FAIL 127, : , FAIL 131, : , [[11], [8, 4, 44, 4, 8, 22]] 137, : , [[11], [5, 5, 4, 10, 4, 5, 5, 22]] 139, : , FAIL 149, : , FAIL 151, : , FAIL 157, : , FAIL 163, : , FAIL 167, : , [[12], [4, 11, 4, 24]] 173, : , [[13], [26]] 179, : , FAIL 181, : , [[13], [8, 4, 4, 8, 26]] 191, : , FAIL 193, : , [[13], [4, 8, 13, 8, 4, 26]] 197, : , [[14], [112, 28]] 199, : , [[14], [37, 8, 9, 5, 18, 56, 18, 5, 9, 8, 37, 28]] 211, : , FAIL 223, : , [[14], [4, 13, 4, 28]] 227, : , [[15], [60, 30]] 229, : , [[15], [30]] 233, : , [[15], [15, 30]] 239, : , FAIL 241, : , FAIL 251, : , FAIL 257, : , [[16], [128, 32]] 263, : , [[16], [18, 9, 5, 14, 4, 6, 5, 31, 5, 6, 4, 14, 5, 9, 18, 32]] 269, : , [[16], [9, 4, 31, 4, 9, 32]] 271, : , FAIL 277, : , FAIL 281, : , [[16], [5, 16, 7, 6, 26, 19, 536, 19, 26, 6, 7, 16, 5, 32]] 283, : , [[16], [4, 4, 6, 14, 10, 4, 15, 4, 10, 14, 6, 4, 4, 32]] 293, : , [[17], [34]] 307, : , FAIL 311, : , [[17], [6, 13, 8, 4, 4, 16, 4, 4, 8, 13, 6, 34]] 313, : , [[17], [5, 5, 34]] 317, : , [[17], [4, 4, 34]] 331, : , [[18], [20, 5, 4, 6, 9, 33, 4, 4, 4, 5, 5, 6, 17, 6, 5, 5, 4, 4, 4, 33, 9, 6, 4, 5, 20, 36]] 337, : , FAIL 347, : , [[18], [6, 10, 4, 4, 17, 4, 4, 10, 6, 36]] 349, : , FAIL 353, : , [[18], [5, 53, 4, 6, 4, 13, 37, 13, 4, 6, 4, 53, 5, 36]] 359, : , [[18], [4, 17, 4, 36]] 367, : , [[19], [25, 9, 31, 4904, 31, 9, 25, 38]] 373, : , [[19], [12, 5, 21, 12, 9, 12, 21, 5, 12, 38]] 379, : , FAIL 383, : , [[19], [7, 312, 7, 38]] 389, : , FAIL 397, : , [[19], [4, 12, 12, 4, 38]] 401, : , [[20], [160, 40]] 409, : , FAIL 419, : , FAIL 421, : , FAIL 431, : , FAIL 433, : , FAIL 439, : , [[20], [4, 19, 4, 40]] 443, : , [[21], [84, 42]] 449, : , [[21], [21, 42]] 457, : , [[21], [10, 6, 5, 8, 13, 5, 84, 5, 13, 8, 5, 6, 10, 42]] 461, : , [[21], [8, 8, 42]] 463, : , [[21], [7, 5, 8, 9, 4, 37, 11, 8, 7, 85, 7, 8, 11, 37, 4, 9, 8, 5, 7, 42]] 467, : , FAIL 479, : , FAIL 487, : , FAIL 491, : , FAIL 499, : , [[22], [11, 4, 4, 5, 4, 177, 4, 5, 4, 4, 11, 44]] 503, : , FAIL 509, : , FAIL 521, : , FAIL 523, : , FAIL 541, : , FAIL 547, : , [[23], [10, 12, 4, 30, 15, 8, 6, 20, 23, 20, 6, 8, 15, 30, 4, 12, 10, 46]] 557, : , [[23], [6, 6, 46]] 563, : , [[23], [5, 8, 94, 8, 5, 46]] 569, : , FAIL 571, : , FAIL 577, : , [[24], [192, 48]] 587, : , FAIL 593, : , [[24], [11, 10, 6, 7, 4, 5, 9, 4, 193, 4, 9, 5, 4, 7, 6, 10, 11, 48]] 599, : , FAIL 601, : , FAIL 607, : , [[24], [6, 14, 7, 4, 15, 7, 12, 24, 12, 7, 15, 4, 7, 14, 6, 48]] 613, : , FAIL 617, : , FAIL 619, : , FAIL 631, : , FAIL 641, : , FAIL 643, : , FAIL 647, : , [[25], [9, 23, 8, 406, 8, 23, 9, 50]] 653, : , [[25], [7, 18, 204, 18, 7, 50]] 659, : , [[25], [5, 4, 24, 4, 5, 50]] 661, : , FAIL 673, : , FAIL 677, : , [[26], [208, 52]] 683, : , [[26], [29, 5, 70, 10, 35, 4, 26, 836, 26, 4, 35, 10, 70, 5, 29, 52]] 691, : , FAIL 701, : , [[26], [8, 10, 41, 4, 51, 4, 41, 10, 8, 52]] 709, : , FAIL 719, : , FAIL 727, : , [[26], [4, 25, 4, 52]] 733, : , [[27], [54]] 739, : , FAIL 743, : , FAIL 751, : , FAIL 757, : , FAIL 761, : , [[27], [6, 4, 4, 6, 54]] 769, : , [[27], [5, 8, 8, 5, 54]] 773, : , [[27], [4, 4, 54]] 787, : , FAIL 797, : , [[28], [17, 13, 16, 81, 4, 7, 8, 5, 55, 5, 8, 7, 4, 81, 16, 13, 17, 56]] 809, : , FAIL 811, : , FAIL 821, : , FAIL 823, : , FAIL 827, : , FAIL 829, : , FAIL 839, : , [[28], [4, 27, 4, 56]] 853, : , [[29], [19, 9, 4, 18, 7, 120, 103, 4, 4, 13, 4, 4, 103, 120, 7, 18, 4, 9, 19, 58]] 857, : , [[29], [14, 7, 116, 7, 14, 58]] 859, : , FAIL 863, : , FAIL 877, : , FAIL 881, : , [[29], [5, 4, 6, 6, 4, 5, 58]] 883, : , FAIL 887, : , FAIL 907, : , FAIL 911, : , FAIL 919, : , FAIL 929, : , [[30], [8, 11, 5, 5, 11, 8, 60]] 937, : , FAIL 941, : , [[30], [5, 4, 11, 9, 20, 5, 156, 13, 4, 4, 980, 4, 4, 13, 156, 5, 20, 9, 11, 4, 5, 60]] 947, : , FAIL 953, : , FAIL 967, : , FAIL 971, : , FAIL 977, : , [[31], [15, 7, 44, 4, 10, 6, 30, 6, 10, 4, 44, 7, 15, 62]] 983, : , [[31], [11, 11, 4, 6, 4, 11, 11, 62]] 991, : , FAIL 997, : , [[31], [6, 4, 20, 20, 4, 6, 62]] 1009, : , FAIL 1013, : , [[31], [4, 4, 4, 4, 62]] 1019, : , FAIL 1021, : , FAIL 1031, : , FAIL 1033, : , [[32], [28, 7, 4, 8, 13, 48, 5, 4, 8, 5, 4, 4, 7, 4, 4, 8, 7, 4, 5, 14, 8, 4, 146, 114, 16, 114, 146, 4, 8, 14, 5, 4, 7, 8, 4, 4, 7, 4, 4, 5, 8, 4, 5, 48, 13, 8, 4, 7, 28, 64]] 1039, : , FAIL 1049, : , [[32], [10, 13, 16, 5, 5, 31, 5, 5, 16, 13, 10, 64]] 1051, : , FAIL 1061, : , FAIL 1063, : , [[32], [6, 6, 10, 14, 4, 28, 86, 4, 4, 31, 4, 4, 86, 28, 4, 14, 10, 6, 6, 64]] 1069, : , FAIL 1087, : , [[32], [4, 31, 4, 64]] 1091, : , [[33], [132, 66]] 1093, : , [[33], [66]] 1097, : , [[33], [33, 66]] 1103, : , [[33], [18, 4, 11, 30, 4, 11, 4, 131, 4, 11, 4, 30, 11, 4, 18, 66]] 1109, : , FAIL 1117, : , [[33], [9, 8, 21, 4, 4, 21, 8, 9, 66]] 1123, : , FAIL 1129, : , [[33], [6, 6, 66]] 1151, : , FAIL 1153, : , [[33], [4, 21, 6, 29, 7, 8, 6, 10, 4, 10, 27, 8, 46, 5, 12, 7, 4, 11, 12, 26, 22, 8, 16, 8, 22, 26, 12, 11, 4, 7, 12, 5, 46, 8, 27, 10, 4, 10, 6, 8, 7, 29, 6, 21, 4, 66]] 1163, : , [[34], [38, 4, 10, 4, 7, 4, 7, 6, 14, 5, 13, 6, 6, 67, 6, 6, 13, 5, 14, 6, 7, 4, 7, 4, 10, 4, 38, 68]] 1171, : , FAIL 1181, : , FAIL 1187, : , FAIL 1193, : , FAIL 1201, : , FAIL 1213, : , [[34], [4, 4, 4, 4, 7, 6, 8, 158, 5, 12, 278, 12, 5, 158, 8, 6, 7, 4, 4, 4, 4, 68] ] 1217, : , FAIL 1223, : , [[34], [4, 33, 4, 68]] Finally, the sequence of periods (for the OEIS) is [4, 2, 2, 4, 2, 1, 2, FAIL, 4, 1, 4, 2, 6, FAIL, 4, 1, 6, 3, FAIL, FAIL, FAIL, 4, 2, 2, FAIL, 2, 8, 8, FAIL, FAIL, FAIL, 6, 8, FAIL, FAIL, FAIL, FAIL, FAIL, 4 , 1, FAIL, 5, FAIL, 6, 2, 12, FAIL, 4, 2, 1, 2, FAIL, FAIL, FAIL, 2, 16, 6, FAIL, FAIL, 14, 14, 1, FAIL, 12, 3, 3, 26, FAIL, 10, FAIL, 14, 4, 8, 10, FAIL, 4, FAIL, 5, 2, FAIL, FAIL, FAIL, FAIL, FAIL, 4, 2, 2, 14, 3, 20, FAIL, FAIL, FAIL, FAIL, 12, FAIL, FAIL, FAIL, FAIL, FAIL, 18, 3, 6, FAIL, FAIL, 2, FAIL, 18 , FAIL, FAIL, 16, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, 8, 6, 6, FAIL, FAIL, 2, 16, FAIL, 10, FAIL, FAIL, 4, 1, FAIL, FAIL, FAIL, FAIL, 5, 5, 3, FAIL, 18, FAIL , FAIL, FAIL, FAIL, FAIL, FAIL, 4, 20, 6, FAIL, FAIL, FAIL, 7, FAIL, FAIL, FAIL , FAIL, FAIL, 7, FAIL, 22, FAIL, FAIL, FAIL, FAIL, 14, 8, FAIL, 7, FAIL, 5, FAIL, FAIL, FAIL, 50, FAIL, 12, FAIL, FAIL, 20, FAIL, 4, 2, 1, 2, 16, FAIL, 9, FAIL, 3, FAIL, 46, 28, FAIL, FAIL, FAIL, FAIL, FAIL, 22, FAIL, 4] This ends this article, that took, 351.394, seconds to generate.