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A091515
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Numbers n such that (2^n - 1)^2 - 2 = 4^n - 2^(n+1) - 1 is prime.
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13
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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
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..44.
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
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MATHEMATICA
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lst={}; Do[p=(2^n-1)^2-2; If[PrimeQ[p], AppendTo[lst, n]], {n, 7!}]; lst (* Vladimir Joseph Stephan Orlovsky, Jan 27 2009 *)
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PROG
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(PARI) is(n)=ispseudoprime((2^n - 1)^2 - 2) \\ Charles R Greathouse IV, Feb 19 2016
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CROSSREFS
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Cf. A093112, A091516.
Sequence in context: A158381 A163180 A341270 * A036405 A051424 A308632
Adjacent sequences: A091512 A091513 A091514 * A091516 A091517 A091518
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KEYWORD
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nonn,hard
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AUTHOR
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Eric W. Weisstein, Jan 17 2004
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EXTENSIONS
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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
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STATUS
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approved
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