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 A295909 #7 Feb 16 2025 08:33:52
%S A295909 2,4,14,30,82,160,386,718,1646,3000,6742,12190,27194,49024,109082,
%T A295909 196446,436726,786232,1747406,3145486,6990242,12582624,27961714,
%U A295909 50331310,111847742,201326200,447392006,805305918,1789569226,3221224960,7158278282,12884901310
%N A295909 Number of (not necessarily maximal) cliques in the n X n black bishop graph.
%H A295909 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/BlackBishopGraph.html">Black Bishop Graph</a>
%H A295909 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Clique.html">Clique</a>
%H A295909 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (2, 4, -10, 1, 8, -4).
%F A295909 a(n) = ((-2)^(n + 1) + (-1)^n + 19*2^(n + 1) - 6*n*(n + 4) - 25)/12.
%F A295909 a(n) = 2*a(n-1) + 4*a(n-2) - 10*a(n-3) + a(n-4) + 8*a(n-5) - 4*a(n-6).
%F A295909 G.f.: -2*x*(-1 + x^2 - 3*x^3 - 2*x^4 + 2*x^5)/((-1 + x)^3 (-1 - x + 4*x^2 + 4*x^3)).
%t A295909 Table[((-2)^(n + 1) + (-1)^n + 19 2^(n + 1) - 6 n (n + 4) - 25)/12, {n, 20}]
%t A295909 LinearRecurrence[{2, 4, -10, 1, 8, -4}, {2, 4, 14, 30, 82, 160}, 20]
%t A295909 CoefficientList[Series[-2 (-1 + x^2 - 3 x^3 - 2 x^4 + 2 x^5)/((-1 + x)^3 (-1 - x + 4 x^2 + 4 x^3)), {x, 0, 20}], x]
%K A295909 nonn
%O A295909 1,1
%A A295909 _Eric W. Weisstein_, Nov 29 2017