OFFSET
1,3
COMMENTS
Leading zeros are not allowed.
2^odd cannot be rearranged to a square number: odd powers of 2 are congruent to 2,5,8 mod 9; squares are congruent to 0,1,4,7 mod 9; and rearranging preserves the mod-9 value.
If it exists, a(9) > 78.
REFERENCES
Don Reble, Posting to Sequence Fans Mailing List, Aug 21 2020
EXAMPLE
4 is not here because 4^4 = 256 -> 625 = 25^2.
10 is not here, because 4^10 = 1048576 -> 1056784 = 1028^2.
11 is here, even though 4^11 = 4194304 -> 0413449 = 643^2, because leading zeros aren't allowed.
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
N. J. A. Sloane, Aug 22 2020
STATUS
approved