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 A265150 #9 Oct 13 2017 03:31:21
%S A265150 10,24,336,400,689,5876,7556,8249,53284,335556,4512400,25092921,
%T A265150 165947209,496186596,3891489129,6897736129,10128495225,18547234816,
%U A265150 81770476100,203672467856,909690622025,6063906517681,14045408555225,50912872680100,145763131189824,180798422222500
%N A265150 a(1) = 10, a(n) = smallest number > a(n-1) such that the concatenation of a(n-1) and a(n) is a square.
%e A265150 a(3) is 336 since it is the least number greater than a(2)=24 which concatenated with 24 forms a perfect square, i.e., 24336 = 156^2.
%t A265150 f[n_] := Block[{x = n, d = 1 + Floor@ Log10@ n}, q = (Floor@ Sqrt[(10^d + 1) x] + 1)^2; If[q < (10^d) (x + 1), Mod[q, 10^d], Mod[(Floor@ Sqrt[(10^d)(10x + 1) - 1] + 1)^2, 10^(d + 1)] ]]; NestList[f, 10, 25] (* after the algorithm of _David W. Wilson_ in A090566 *)
%Y A265150 Cf. A090566, A265147, A265148, A265149, A265151, A265152, A265153, A265154, A265155.
%K A265150 nonn,base
%O A265150 1,1
%A A265150 _Robert G. Wilson v_, Dec 02 2015