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A167720
Squares that become a prime number when prefixed with a 5.
1
9, 441, 1521, 12321, 19881, 29241, 59049, 74529, 95481, 123201, 168921, 199809, 227529, 263169, 288369, 328329, 356409, 370881, 385641, 471969, 480249, 488601, 531441, 558009, 594441, 603729, 613089, 622521, 690561, 741321, 804609, 826281
OFFSET
1,1
COMMENTS
Subsequence of squares of A032668. - Michel Marcus, Jun 21 2016
LINKS
MATHEMATICA
Select[Range[1, 500, 2]^2, PrimeQ[FromDigits[Join[{5}, IntegerDigits[#]]]] &] (* G. C. Greubel, Jun 20 2016 *)
CROSSREFS
Cf. A032668.
Sequence in context: A242280 A266294 A273889 * A287102 A173954 A239479
KEYWORD
base,nonn
AUTHOR
Claudio Meller, Nov 10 2009
STATUS
approved