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 A115547 #11 Jul 15 2021 09:14:37 %S A115547 11909262759924385633270321361058601134215500945179584121, %T A115547 21172022684310018903591682419659735349716446124763705104, %U A115547 33081285444234404536862003780718336483931947069943289225,47637051039697542533081285444234404536862003780718336484 %N A115547 Numbers k such that the concatenation of 7*k with k gives a square. %Y A115547 Cf. A102567, A106497, A115527 - A115556. %K A115547 nonn,base %O A115547 1,1 %A A115547 _Giovanni Resta_, Jan 25 2006