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 A356213 #34 Aug 11 2024 22:08:16
%S A356213 4,104,1699,23904,317044,4101107,52473796,668177568,8490113467,
%T A356213 107776172264,1367566963756,17349734444643,220090218116188,
%U A356213 2791852592070632,35414167120396459,449219270600324928,5698208011194600148,72279907017666274643,916846410588661477204
%N A356213 Number of edge covers in the n-trapezohedral graph.
%C A356213 Sequence extended to n = 1 using the formula/recurrence.
%H A356213 Christian Sievers, <a href="/A356213/b356213.txt">Table of n, a(n) for n = 1..200</a>
%H A356213 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/EdgeCover.html">Edge Cover</a>
%H A356213 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TrapezohedralGraph.html">Trapezohedral Graph</a>
%H A356213 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (22,-142,321,-242,74,-8).
%F A356213 a(n) = 22*a(n-1) - 142*a(n-2) + 321*a(n-3) - 242*a(n-4) + 74*a(n-5) - 8*a(n-6) for n > 6.
%F A356213 G.f.: -(-2+x)*x*(2+9*x-6*x^2+2*x^3)/((1-3*x+x^2)*(1-6*x+2*x^2)*(1-13*x+4*x^2)).
%t A356213 Table[LucasL[2 n] - 2 ((3 - Sqrt[7])^n + (3 + Sqrt[7])^n) + ((13 - 3 Sqrt[17])^n + (13 + 3 Sqrt[17])^n)/2^n, {n, 20}] // Expand (* _Eric W. Weisstein_, May 26 2024 *)
%t A356213 LinearRecurrence[{22, -142, 321, -242, 74, -8}, {4, 104, 1699, 23904, 317044, 4101107}, 20] (* _Eric W. Weisstein_, May 26 2024 *)
%t A356213 CoefficientList[Series[-(((-2 + x) (2 + 9 x - 6 x^2 + 2 x^3))/((1 - 3 x + x^2) (1 - 6 x + 2 x^2) (1 - 13 x + 4 x^2))), {x, 0, 20}], x] (* _Eric W. Weisstein_, May 26 2024 *)
%Y A356213 Cf. A297047.
%K A356213 nonn
%O A356213 1,1
%A A356213 _Eric W. Weisstein_, Jul 29 2022
%E A356213 a(9)-a(12) from _Andrew Howroyd_, Jan 27 2023
%E A356213 More terms from _Christian Sievers_, Nov 20 2023
%E A356213 a(1)-a(2) prepended by _Eric W. Weisstein_, May 26 2024
%E A356213 Offset updated for a(1)-a(2) by _Sean A. Irvine_, Aug 11 2024