

A112559


Numbers k such that both k and 4k + 1 are in A005098.


2



3, 9, 18, 24, 48, 69, 93, 102, 108, 144, 168, 177, 213, 249, 258, 273, 282, 324, 357, 363, 387, 399, 438, 444, 504, 507, 573, 609, 669, 678, 738, 759, 762, 777, 807, 864, 867, 909, 942, 948, 963, 1014, 1068, 1074, 1182, 1197, 1248, 1299, 1389, 1392, 1413, 1488
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OFFSET

1,1


COMMENTS

All terms are multiples of 3.
Numbers k such that 4*k+1 and 16*k+5 are both prime.  Vincenzo Librandi, Dec 13 2010
These k cannot have least significant digits 0, 1, 5, or 6.  J. M. Bergot, Jul 06 2011


LINKS

R. J. Mathar, Table of n, a(n) for n = 1..1738


FORMULA

a(n) = 3 * A179652(n).  Joerg Arndt, Jul 10 2011


PROG

(Magma) [n: n in [0..3000]  IsPrime(4*n+1)and IsPrime(16*n+5)] // Vincenzo Librandi, Dec 13 2010


CROSSREFS

Cf. A002144, A175600.
Sequence in context: A360365 A310332 A210991 * A030784 A203594 A325751
Adjacent sequences: A112556 A112557 A112558 * A112560 A112561 A112562


KEYWORD

nonn


AUTHOR

Zak Seidov, May 26 2007


STATUS

approved



