Number of closed walks of length n at a vertex of the cyclic graph on 7 nodes C_7.

Terms

a(0) =1a(1) =0a(2) =2a(3) =0a(4) =6a(5) =0a(6) =20a(7) =2a(8) =70a(9) =18a(10) =252a(11) =110a(12) =924a(13) =572a(14) =3434a(15) =2730a(16) =12902a(17) =12376a(18) =48926a(19) =54264a(20) =187036a(21) =232562a(22) =720062a(23) =980674a(24) =2789164a(25) =4086550a(26) =10861060a(27) =16878420a(28) =42484682a(29) =69242082