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 A290591 #13 Feb 16 2025 08:33:50 %S A290591 4,22,112,618,3044,14026,70340,347074,1713820,8430362,41516292, %T A290591 204628626,1008216460,4967464650,24473678612,120581823170, %U A290591 594106884060,2927147525626,14421969381220,71056635221618,350094259434668,1724905262555178,8498562511858612 %N A290591 Number of irredundant sets in the n-web graph. %C A290591 The n-web graph is well defined for n >= 3. Sequence extended to n=1 via the number of period n periodic solutions on a larger graph. - _Andrew Howroyd_, Aug 07 2017 %H A290591 Andrew Howroyd, <a href="/A290591/b290591.txt">Table of n, a(n) for n = 1..200</a> %H A290591 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/IrredundantSet.html">Irredundant Set</a> %H A290591 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/WebGraph.html">Web Graph</a> %F A290591 From _Andrew Howroyd_, Aug 07 2017: (Start) %F A290591 Empirical: a(n) = 4*a(n-1) + 3*a(n-2) + 4*a(n-3) + 22*a(n-4) + 12*a(n-5) - 164*a(n-6) + 80*a(n-7) - 24*a(n-8) + 80*a(n-9) for n > 9. %F A290591 Empirical g.f.: 2*x*(2 + 3*x + 6*x^2 + 44*x^3 + 30*x^4 - 492*x^5 + 280*x^6 - 96*x^7 + 360*x^8)/(1 - 4*x - 3*x^2 - 4*x^3 - 22*x^4 - 12*x^5 + 164*x^6 - 80*x^7 + 24*x^8 - 80*x^9). %F A290591 (End) %Y A290591 Cf. A287474, A290381. %K A290591 nonn %O A290591 1,1 %A A290591 _Eric W. Weisstein_, Aug 07 2017 %E A290591 a(1)-a(2) and terms a(8) and beyond from _Andrew Howroyd_, Aug 07 2017