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 A115433 #5 Jul 15 2021 06:21:18 %S A115433 21,30,902406,959721,6040059046,6242406405,9842410005,9900249006, %T A115433 15033519988494,17250863148969,22499666270469,27632040031654, %U A115433 34182546327286,37487353123861,52213551379230,74230108225630 %N A115433 Numbers k such that the concatenation of k with k-5 gives a square. %e A115433 902406_902401 = 949951^2. %Y A115433 Cf. A030465, A102567, A115426, A115437, A115428, A115429, A115430, A115431, A115432, A115434, A115435, A115436, A115444. %K A115433 base,nonn %O A115433 1,1 %A A115433 _Giovanni Resta_, Jan 25 2006