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 A171841 #6 Jun 02 2025 02:23:08 %S A171841 1,3,8,22,68,241,974,4410,21969,118698,688301,4250788 %N A171841 Row sums of triangle A171840. %e A171841 a(4) = 22 = (1 + 2 + 4 + 15) since (1, 2, 4, 15) = row 4 of triangle A171840. %Y A171841 Cf. A171840 %K A171841 nonn %O A171841 1,2 %A A171841 _Gary W. Adamson_, Dec 19 2009