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 A360874 #12 Oct 03 2024 08:05:40
%S A360874 3,13,51,205,843,3493,14451,59485,243483,991573,4021251,16253965,
%T A360874 65530923,263685253,1059458451,4252051645,17050991163,68332580533,
%U A360874 273716694051,1096026940525,4387590352203,17560813373413,70274617776051,281192580728605,1125052685342043
%N A360874 Number of (non-null) connected induced subgraphs in the 2 X n rook graph.
%H A360874 Andrew Howroyd, <a href="/A360874/b360874.txt">Table of n, a(n) for n = 1..1000</a>
%H A360874 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (10,-35,50,-24).
%F A360874 a(n) = 10*a(n-1) - 35*a(n-2) + 50*a(n-3) - 24*a(n-4) for n > 4.
%F A360874 G.f.: x*(3 - 17*x + 26*x^2)/((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)).
%t A360874 LinearRecurrence[{10, -35, 50, -24}, {3, 13, 51, 205}, 30] (* _Paolo Xausa_, Oct 03 2024 *)
%o A360874 (PARI) Vec((3 - 17*x + 26*x^2)/((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)) + O(x^25))
%Y A360874 Row 2 of A360873.
%Y A360874 Cf. A360876.
%K A360874 nonn,easy
%O A360874 1,1
%A A360874 _Andrew Howroyd_, Feb 24 2023