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 A241227 #13 Feb 16 2025 08:33:22 %S A241227 0,12,648,6084,30444,107376,302916,732024,1576728,3111012,5724852, %T A241227 9952620,16509336,26321160,40567872,60724104,88605480,126413772, %U A241227 176788476,242874756,328359624,437553360 %N A241227 Number of scalene triangles on a centered hexagonal grid of size n. %C A241227 A centered hexagonal grid of size n is a grid with A003215(n-1) points forming a hexagonal lattice. %H A241227 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HexNumber.html">Hex Number</a>. %H A241227 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ScaleneTriangle.html">Scalene Triangle</a>. %F A241227 a(n) = A241223(n) - A241228(n). %Y A241227 Cf. A190312. %K A241227 nonn,more %O A241227 1,2 %A A241227 _Martin Renner_, Apr 17 2014 %E A241227 a(7) from _Martin Renner_, May 31 2014 %E A241227 a(8)-a(22) from _Giovanni Resta_, May 31 2014