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 A115551 #6 Jul 15 2021 09:12:48 %S A115551 1,4,9,89,889,8889,88889,888889,8888889,88888889,888888889,1026765584, %T A115551 1066636289,1107266436,1148656025,1190805056,1233713529,1277381444, %U A115551 1321808801,1366995600,1412941841,1459647524,1507112649,1555337216 %N A115551 Numbers k such that the concatenation of 8*k with k gives a square. %e A115551 8_1 = 9^2. %Y A115551 Cf. A102567, A106497, A115527 - A115556. %K A115551 nonn,base %O A115551 1,2 %A A115551 _Giovanni Resta_, Jan 25 2006