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 A297671 #8 Feb 16 2025 08:33:52 %S A297671 0,0,0,1,7,41,260,1930,17463,200008,3026192,62212319,1742874972, %T A297671 65794989216,3314857545154,222226981778153,19858056830333695, %U A297671 2371636836808937036,378993965527624639893 %N A297671 Number of chordless cycles in the n-triangular grid graph. %H A297671 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ChordlessCycle.html">Chordless Cycle</a> %H A297671 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TriangularGridGraph.html">Triangular Grid Graph</a> %Y A297671 Cf. A112676, A266513. %K A297671 nonn,more %O A297671 0,5 %A A297671 _Eric W. Weisstein_, Jan 02 2018 %E A297671 a(7)-a(18) from _Andrew Howroyd_, Jan 08 2018