read UGJ: print(`This is a simple example of an Umbral Scheme for`): print(`for generating functions for enumerating words in {1,2,3}`): print(`that avoid 3 consecutive 1's, and any factor of the form`): print(` 12^(a+1)1^(a+b+1)3^(b+1)1 , for all a,b>=0 `): ListSW:= [ [[[1,1],[2,a+1],[1,a+b+1],[3,b+1],[1,1]],[a,b]], [[[1,3]],[]] ]: lu:=UmSc(ListSW,x,t): print(`The Umbral Scheme is`): print(YafeUmSc(lu,F,D)); print(`Using this Umbral Scheme, the first 30 terms of the`): print(`generating function are`): gu:=UGJseries(ListSW,3,30): print(gu): print(`The whole thing took`, time(), `minutes of CPU time `): quit: