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 A065788 #6 Jun 12 2023 19:38:27
%S A065788 64,1764,6041764,96126041764,8584885596126041764,
%T A065788 1094573934406914368584885596126041764,
%U A065788 164840278246153785356947805564195221094573934406914368584885596126041764
%N A065788 a(1) = 64; for n > 1 a(n) is the smallest square > a(n-1) with a(n-1) forming its final digits.
%C A065788 a(n) = A050636(n+1) for n >= 1.
%t A065788 nxt[n_]:=Module[{k=1},While[!IntegerQ[Sqrt[k*10^IntegerLength[n]+n]],k++];k*10^IntegerLength[n]+n]; NestList[nxt,64,6] (* _Harvey P. Dale_, Dec 14 2019 *)
%Y A065788 A050634, A050636, A065689, A065789, A065790.
%K A065788 base,nonn
%O A065788 1,1
%A A065788 _Klaus Brockhaus_, Nov 19 2001