Closed walks of length n along the edges of a pentagon based at a vertex.

Terms

a(0) =1a(1) =0a(2) =2a(3) =0a(4) =6a(5) =2a(6) =20a(7) =14a(8) =70a(9) =72a(10) =254a(11) =330a(12) =948a(13) =1430a(14) =3614a(15) =6008a(16) =13990a(17) =24786a(18) =54740a(19) =101118a(20) =215766a(21) =409640a(22) =854702a(23) =1652090a(24) =3396916a(25) =6643782a(26) =13530350a(27) =26667864a(28) =53971350a(29) =106914242