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 A115427 #5 Jul 15 2021 06:17:49 %S A115427 8874,9011,83352842,99000101,329767122288,670232877713,738226276373, %T A115427 933006600341,999000001001,3779410975143115,3872816717528067, %U A115427 4250291784692550,4278630943941867,4372036686326819,4749511753491302 %N A115427 Numbers k such that k^2 is the concatenation of two numbers m and m+2. %e A115427 9011^2 = 8119_8121. %Y A115427 Cf. A030467, A106497, A115426, A115438, A115439, A115440, A115441, A115442, A115443, A115444, A115445, A115446, A115447. %K A115427 base,nonn %O A115427 1,1 %A A115427 _Giovanni Resta_, Jan 24 2006