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 A168139 #5 Oct 15 2013 10:59:59 %S A168139 0,1,4,9,1521,1681,2025,2304,2601,3364,3481,3600,4489,4624,5776,5929, %T A168139 7225,7396,8100,8836,9025,100000000,100020001,100040004,100060009, %U A168139 100080016,100100025,100200100,100220121,100240144,100260169,100400400 %N A168139 Squares whose sum and number of digits are also squares. %e A168139 1521=39^2, number of digits = 4, number of digits = 1+5+2+1=9. %o A168139 (PARI) isok(n) = issquare(n) && issquare(sumdigits(n)) && issquare(length(Str(n))); \\ _Michel Marcus_, Oct 15 2013 %Y A168139 Subsequence of A053057 (with additional first term = 0). %K A168139 base,nonn %O A168139 1,3 %A A168139 _Zak Seidov_, Nov 19 2009