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 A338723 #9 Nov 30 2020 22:27:38 %S A338723 1,3,4,6,6,9,9,11,13,14,14,18,18,18,21,23,23,25,25,29,30,30,30,34,36, %T A338723 36,36,39,39,43,43,45,45,45,49,52,52,52,52,56,56,60,60,60,63,63,63,67, %U A338723 69,71,71,71,71,75,76,80,80,80,80,84,84,84,88,90,90,93,93 %N A338723 Alternating row sums in triangle A338721. %H A338723 Alois P. Heinz, <a href="/A338723/b338723.txt">Table of n, a(n) for n = 1..10000</a> %Y A338723 Cf. A338721, A338722. %K A338723 nonn %O A338723 1,2 %A A338723 _N. J. A. Sloane_, Nov 30 2020 %E A338723 More terms from _Alois P. Heinz_, Nov 30 2020