This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A101501 #11 Apr 09 2022 17:41:14
%S A101501 0,1,0,12,8,160,224,2240,4608,32512,84480,485376,1464320,7401472,
%T A101501 24608768,114606080,406093824,1793720320,6626869248,28280881152,
%U A101501 107384668160,448110002176,1732341923840,7123849183232,27866041417728
%N A101501 Number of walks between adjacent nodes on C_5 tensor J_2.
%C A101501 Let (C_5 tensor J_2) be the 10 node graph whose adjacency matrix is the tensor product of that of C_5 and J_2=[1,1;1,1]. Then a(n) counts walks of length n between adjacent vertices of this graph.
%D A101501 E.R. van Dam, Graphs with few eigenvalues, Tilburg, 1968, p53.
%H A101501 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (2,12,-16).
%F A101501 G.f.: x(1-2x)/((1-4x)(1+2x-4x^2)); a(n)=2a(n-1)+12a(n-2)-16a(n-3); a(n)=(sqrt(5)-1)^(n+1)/20-(sqrt(5)+1)^(n+1)(-1)^n/20+4^n/10; a(n)=sum{k=0..n, sqrt(5)((sqrt(5)-1)^k/10-(-sqrt(5)-1)^k/10)(4^(n-k)+0^(n-k))/2}.
%F A101501 (1/10) [4^n - (-2)^n*Lucas(n+1) ]. - _Ralf Stephan_, May 16 2007
%F A101501 a(n) = 2^(n-1)*A052964(n-1). - _R. J. Mathar_, Mar 08 2021
%t A101501 LinearRecurrence[{2,12,-16},{0,1,0},30] (* _Harvey P. Dale_, Apr 09 2022 *)
%Y A101501 Cf. A101502.
%K A101501 nonn,easy
%O A101501 0,4
%A A101501 _Paul Barry_, Dec 04 2004