Number of walks of length n between two nodes at distance 2 in the cycle graph C_9.

Terms

a(0) =1a(1) =0a(2) =4a(3) =0a(4) =15a(5) =1a(6) =56a(7) =9a(8) =210a(9) =56a(10) =792a(11) =299a(12) =3003a(13) =1470a(14) =11441a(15) =6868a(16) =43776a(17) =31008a(18) =168151a(19) =136629a(20) =648208a(21) =591261a(22) =2507046a(23) =2523676a(24) =9726080a(25) =10656387a(26) =37839375a(27) =44612702a(28) =147600981a(29) =185477216