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A171140
Numbers k such that 6*k + 7 = p^2 (p=prime).
1
3, 7, 19, 27, 47, 59, 87, 139, 159, 227, 279, 307, 367, 467, 579, 619, 747, 839, 887, 1039, 1147, 1319, 1567, 1699, 1767, 1907, 1979, 2127, 2687, 2859, 3127, 3219, 3699, 3799, 4107, 4427, 4647, 4987, 5339, 5459, 6079, 6207, 6467, 6599, 7419, 8287, 8587
OFFSET
1,1
COMMENTS
Subsequence of A164097. - R. J. Mathar, Jul 06 2010
LINKS
EXAMPLE
6*3 + 7 = 5^2, so 3 is a term;
6*7 + 7 = 7^2, so 7 is a term;
6*19 + 7 = 11^2, so 19 is a term;
6*27 + 7 = 13^2, so 27 is a term.
MATHEMATICA
Select[Range[10000], PrimeQ[Sqrt[6 # + 7]]&] (* Vincenzo Librandi, Apr 06 2013 *)
PROG
(Magma) [(p^2-7)/6: p in PrimesInInterval(4, 250)]; // Vincenzo Librandi, Apr 06 2013
CROSSREFS
Cf. A164097.
Sequence in context: A203319 A366171 A164097 * A186452 A016046 A239219
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Dec 04 2009
STATUS
approved