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A167719
Squares that become a prime number when prefixed with a 4
1
1, 49, 289, 441, 729, 1521, 1681, 1849, 2209, 3481, 3721, 3969, 5329, 6889, 7569, 8281, 8649, 9409, 9801, 11449, 13689, 14641, 17161, 21609, 25281, 29241, 29929, 31329, 36481, 39601, 47961, 61009, 67081, 68121, 69169, 73441, 88209, 97969
OFFSET
1,2
LINKS
MATHEMATICA
Select[Range[1, 811, 2]^2, PrimeQ[FromDigits[Join[{4}, IntegerDigits[#]]]]&] (* Harvey P. Dale, Oct 16 2011 *)
CROSSREFS
Sequence in context: A020274 A158248 A219030 * A239211 A198437 A144407
KEYWORD
base,nonn
AUTHOR
Claudio Meller, Nov 10 2009
STATUS
approved