A168139 Squares whose sum and number of digits are also squares.

0, 1, 4, 9, 1521, 1681, 2025, 2304, 2601, 3364, 3481, 3600, 4489, 4624, 5776, 5929, 7225, 7396, 8100, 8836, 9025, 100000000, 100020001, 100040004, 100060009, 100080016, 100100025, 100200100, 100220121, 100240144, 100260169, 100400400

Offset: 1

Author

Zak Seidov, Nov 19 2009

Keywords

• base
• nonn

Examples

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

Crossrefs

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

Programs

PARI

isok(n) = issquare(n) && issquare(sumdigits(n)) && issquare(length(Str(n))); \\ Michel Marcus, Oct 15 2013