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 A027239 #9 Oct 26 2019 15:38:35 %S A027239 1,2,6,26,99,456,1898,9014,39336,190852,859314,4240598,19544133, %T A027239 97854958,459521694,2330612590,11118124352,57054108568,275911990190, %U A027239 1431214323258,7005088758798,36699584733594,181565142550974,959959866168434,4795243608222520,25566993157191804 %N A027239 Self-convolution of row n of array T given by A026769. %K A027239 nonn %O A027239 0,2 %A A027239 _Clark Kimberling_ %E A027239 More terms from _Sean A. Irvine_, Oct 26 2019