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 A115538 #9 Jul 15 2021 09:17:17 %S A115538 84210526316,105263157895,126315789474,147368421053,168421052632, %T A115538 189473684211,114285714285714286,171428571428571429, %U A115538 7058823529411764705882352941176470588235294117647059 %N A115538 Numbers k such that k^2 is the concatenation of two numbers 4*m and m. %e A115538 84210526316^2 = 70914127424_17728531856. %Y A115538 Cf. A102567, A106497, A115527 - A115556. %K A115538 nonn,base %O A115538 1,1 %A A115538 _Giovanni Resta_, Jan 25 2006 %E A115538 Definition modified by _Georg Fischer_, Jul 26 2019