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 A115436 #5 Jul 15 2021 06:23:08 %S A115436 50,5234,9410,638370,994010,12477933,41829698,99940010,1087279650, %T A115436 4492494893,6226356365,7765453730,9999400010,806057802450, %U A115436 842377434050,960398039610,999994000010,21338126513658,24752544267698 %N A115436 Numbers k such that the concatenation of k with k-9 gives a square. %e A115436 638370_638361 = 798981^2. %Y A115436 Cf. A030465, A102567, A115426, A115437, A115428, A115429, A115430, A115431, A115432, A115433, A115434, A115435, A115447. %K A115436 base,nonn %O A115436 1,1 %A A115436 _Giovanni Resta_, Jan 25 2006