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Search: id:A100484
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| 4, 6, 10, 14, 22, 26, 34, 38, 46, 58, 62, 74, 82, 86, 94, 106, 118, 122, 134, 142, 146, 158, 166, 178, 194, 202, 206, 214, 218, 226, 254, 262, 274, 278, 298, 302, 314, 326, 334, 346, 358, 362, 382, 386, 394, 398, 422, 446, 454, 458, 466, 478, 482, 502, 514, 526
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Essentially the same as A001747.
n>1: A000005(a(n))=4; A000203(a(n))=3*A008864(n); A000010(a(n))=A006093(n); intersection of A001358 and A005843.
a(n) = A116366(n-1,n-1) for n>1. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 06 2006
Twice the prime numbers. - Omar E. Pol (info(AT)polprimos.com), May 14 2008
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LINKS
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Eric Weisstein's World of Mathematics, Semiprime
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FORMULA
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a(n) = 2 * A000040(n).
a(n)=A077017(n+1), n>1. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 02 2008]
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MATHEMATICA
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Prime[Range[22]]*2 - Vladimir Orlovsky (4vladimir(AT)gmail.com), Apr 29 2008
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CROSSREFS
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Cf. A046315, a(n)=A001747(n+1).
Cf. A152099.
Sequence in context: A165779 A137860 A091376 this_sequence A076924 A103801 A141247
Adjacent sequences: A100481 A100482 A100483 this_sequence A100485 A100486 A100487
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 22 2004
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EXTENSIONS
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An alternative sequence that gives A100484 functionally: a(n)=Length[IntegerDigits[(2^Prime[n] - 1)*(2^Prime[n] + 1), 2]]. Roger L. Bagula and Artur Jasinski (grafix(AT)csl.pl) (rlbagulatftn(AT)yahoo.com), Nov 28 2008
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