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A168139
Squares whose sum and number of digits are also squares.
0
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
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
KEYWORD
base,nonn
AUTHOR
Zak Seidov, Nov 19 2009
STATUS
approved