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

1,3

Links

Table of n, a(n) for n=1..32.

Example

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

Prog

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

Crossrefs

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

Sequence in context: A028869 A179935 A073172 * A258660 A260305 A229338

Adjacent sequences: A168136 A168137 A168138 * A168140 A168141 A168142

Keyword

base,nonn

Author

Zak Seidov, Nov 19 2009

Status

approved