read W1Dp: S:={[1,1/2],[-1,1/4],[-2,1/4]}: gu:=InfoHp(S,n,N,10): k:=-min(seq(S[i][1],i=1..nops(S)))-1: print(`The linear recurrence operator annihilating the sequence of probabilities for n-step walks with the probability distribution`): print(S): print(`that start at 0, never go to the negatives, and end anywhere on the non-negatives`): print(`where N is the shift operator in n, (followed by the initial conditions) is:`): print(``): print(gu[1]): print(``): print(`and in Maple input notation`): print(``): lprint(gu[1]): print(``): for i from 0 to nops(gu[2])-1 do print(`The linear recurrence operator for those walks that end exactly at`, i, ` (followed by the initial conditions) is `): print(``): print(gu[2][i+1]): print(``): print(`and in Maple input notation`): print(``): lprint(gu[2][i+1]): od: print(`This took`, time(), `seconds. `): quit: