Number of walks of length n between two nodes at distance 2 in the cycle graph C_7.

Terms

a(0) =1a(1) =0a(2) =4a(3) =1a(4) =15a(5) =7a(6) =56a(7) =37a(8) =210a(9) =176a(10) =793a(11) =793a(12) =3017a(13) =3458a(14) =11561a(15) =14756a(16) =44592a(17) =62017a(18) =172995a(19) =257775a(20) =674520a(21) =1062601a(22) =2641366a(23) =4352660a(24) =10381281a(25) =17742621a(26) =40927033a(27) =72048354a(28) =161766061a(29) =291693136