Number of three-dimensional prudent n-step walks.

Terms

a(0) =1a(1) =6a(2) =30a(3) =150a(4) =726a(5) =3510a(6) =16734a(7) =79518a(8) =375246a(9) =1766382a(10) =8278638a(11) =38721366a(12) =180556206a(13) =840524742a(14) =3903866526a(15) =18106798830a(16) =83832778110a(17) =387690560718