A168139 - OEIS

%I #5 Oct 15 2013 10:59:59

%S 0,1,4,9,1521,1681,2025,2304,2601,3364,3481,3600,4489,4624,5776,5929,

%T 7225,7396,8100,8836,9025,100000000,100020001,100040004,100060009,

%U 100080016,100100025,100200100,100220121,100240144,100260169,100400400

%N Squares whose sum and number of digits are also squares.

%e 1521=39^2, number of digits = 4, number of digits = 1+5+2+1=9.

%o (PARI) isok(n) = issquare(n) && issquare(sumdigits(n)) && issquare(length(Str(n))); \\ _Michel Marcus_, Oct 15 2013

%Y Subsequence of A053057 (with additional first term = 0).

%K base,nonn

%O 1,3

%A _Zak Seidov_, Nov 19 2009