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Search: id:A091515
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| A091515 |
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Indices n of Carol (or near-square) primes: numbers n such that (2^n-1)^2-2 = 4^n-2^{n+1}-1 is prime. |
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9
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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
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Steven Harvey, Carol and Kynea Primes.
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 [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Jan 27 2009]
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CROSSREFS
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Cf. A093112 (Carol numbers), A091516 (Carol primes).
Sequence in context: A049806 A158381 A163180 this_sequence A036405 A051424 A137606
Adjacent sequences: A091512 A091513 A091514 this_sequence A091516 A091517 A091518
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KEYWORD
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nonn,hard
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AUTHOR
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Eric Weisstein (eric(AT)weisstein.com), 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 (rayjchandler(AT)sbcglobal.net), Nov 15, 2004
a(38)=226749 from Steven Harvey (harvey563(AT)yahoo.com), Jan 11 2005 and subsequently confirmed as next term.
a(39) from Eric Weisstein (eric(AT)weisstein.com), Mar 31, 2006
a(40)=253987 from Cletus Emmanuel (cemmanu(AT)yahoo.com), May 03 2007
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