login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A214289
Numbers k such that 2*k^3 - 1 is prime.
5
3, 4, 6, 10, 16, 21, 24, 25, 31, 34, 43, 46, 54, 55, 58, 61, 64, 69, 81, 90, 91, 93, 99, 108, 120, 126, 130, 139, 141, 154, 166, 178, 181, 189, 198, 199, 205, 210, 213, 214, 223, 241, 249, 255, 259, 273, 285, 295, 331, 334, 336, 346, 348, 351, 354, 366, 369, 370, 373, 375, 376, 378
OFFSET
1,1
LINKS
FORMULA
A177105(n) = 2*n^3 - 1. - R. J. Mathar, Aug 20 2019
MATHEMATICA
Select[Range[0, 1000], PrimeQ[2*#^3-1]&]
PROG
(Magma) [n: n in [1..400]|IsPrime(2*n^3-1)]
(PARI) is(n)=isprime(2*n^3-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Cf. A177105.
Sequence in context: A139463 A287067 A310004 * A310005 A355325 A068922
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Jul 25 2012
STATUS
approved