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 A049699 #7 Aug 06 2021 17:34:13 %S A049699 1,5,9,14,21,30,37,48,61,72,87,104,115,136,157,172,197,222,239,268, %T A049699 297,318,347,382,407,440,479,506,547,592,619,666,705,738,789,832,867, %U A049699 920,977,1014,1071,1132,1167,1232,1297,1338,1401,1468,1515,1582,1653,1704 %N A049699 a(n) = T(n,n+3), array T as in A049695. %K A049699 nonn %O A049699 0,2 %A A049699 _Clark Kimberling_ %E A049699 More terms from _Sean A. Irvine_, Aug 06 2021