A091515 Numbers k such that (2^k - 1)^2 - 2 = 4^k - 2^(k+1) - 1 is prime.
2, 3, 4, 6, 7, 10, 12, 15, 18, 19, 21, 25, 27, 55, 129, 132, 159, 171, 175, 315, 324, 358, 393, 435, 786, 1459, 1707, 2923, 6462, 14289, 39012, 51637, 100224, 108127, 110953, 175749, 185580, 226749, 248949, 253987, 520363, 653490, 688042, 695631
Offset: 1
Links
- Steven Harvey, Carol and Kynea Primes
- M. Rodenkirch, Carol and Kynea Prime Search
- Eric Weisstein's World of Mathematics, Near-Square Prime
- Eric Weisstein's World of Mathematics, Integer Sequence Primes
Programs
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Mathematica
lst={};Do[p=(2^n-1)^2-2;If[PrimeQ[p],AppendTo[lst,n]],{n,7!}];lst (* Vladimir Joseph Stephan Orlovsky, Jan 27 2009 *) -
PARI
is(n)=ispseudoprime((2^n - 1)^2 - 2) \\ Charles R Greathouse IV, Feb 19 2016
Extensions
More terms from Pab Ter (pabrlos(AT)yahoo.com), May 25 2004
a(36)=175749 from Cletus Emmanuel (cemmanu(AT)yahoo.com), Oct 08 2004
a(37)=185580 from Cletus Emmanuel (cemmanu(AT)yahoo.com), Nov 03 2004
Edited by Ray Chandler, Nov 15 2004
a(38)=226749 from Steven Harvey, Jan 11 2005 and subsequently confirmed as next term
a(39) from Eric W. Weisstein, Mar 31 2006
a(40) = 253987 from Cletus Emmanuel (cemmanu(AT)yahoo.com), May 03 2007
a(41) = 520363 from Eric W. Weisstein, Jun 08 2016 (computed by Mark Rodenkirch)
a(42) = 653490 from Eric W. Weisstein, Jun 15 2016 (computed by Mark Rodenkirch)
a(43) = 688042 from Mark Rodenkirch, Jul 05 2016
a(44) = 695631 from Mark Rodenkirch, Jul 16 2016