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 A049712 #8 Aug 07 2021 00:10:18
%S A049712 1,6,16,38,69,120,190,276,387,542,714,924,1161,1456,1794,2174,2597,
%T A049712 3084,3620,4230,4891,5610,6418,7292,8213,9248,10366,11566,12827,14200,
%U A049712 15664,17228,18865,20690,22546,24498,26625,28826
%N A049712 a(n) = Sum_{i=0..n} T(i,n-i), array T as in A048149.
%K A049712 nonn
%O A049712 0,2
%A A049712 _Clark Kimberling_