Number of walks of length n between two nodes at distance 4 in the cycle graph C_9.

Terms

a(0) =1a(1) =1a(2) =6a(3) =7a(4) =28a(5) =36a(6) =120a(7) =165a(8) =495a(9) =716a(10) =2003a(11) =3018a(12) =8024a(13) =12512a(14) =31977a(15) =51357a(16) =127110a(17) =209475a(18) =504736a(19) =850840a(20) =2003784a(21) =3445885a(22) =7956715a(23) =13926276a(24) =31609071a(25) =56191734a(26) =125640180a(27) =226444616a(28) =499685777a(29) =911607609