Search: id:A100484
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%I A100484
%S A100484 4,6,10,14,22,26,34,38,46,58,62,74,82,86,94,106,118,122,134,142,146,158,
%T A100484 166,178,194,202,206,214,218,226,254,262,274,278,298,302,314,326,334,
%U A100484 346,358,362,382,386,394,398,422,446,454,458,466,478,482,502,514,526
%N A100484 Even semiprimes.
%C A100484 Essentially the same as A001747.
%C A100484 n>1: A000005(a(n))=4; A000203(a(n))=3*A008864(n); A000010(a(n))=A006093(n); 
               intersection of A001358 and A005843.
%C A100484 a(n) = A116366(n-1,n-1) for n>1. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), 
               Feb 06 2006
%C A100484 Twice the prime numbers. - Omar E. Pol (info(AT)polprimos.com), May 14 
               2008
%H A100484 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               Semiprime.html">Semiprime</a>
%F A100484 a(n) = 2 * A000040(n).
%F A100484 a(n)=A077017(n+1), n>1. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               Sep 02 2008]
%t A100484 Prime[Range[22]]*2 - Vladimir Orlovsky (4vladimir(AT)gmail.com), Apr 
               29 2008
%Y A100484 Cf. A046315, a(n)=A001747(n+1).
%Y A100484 Cf. A152099.
%Y A100484 Sequence in context: A165779 A137860 A091376 this_sequence A076924 A103801 
               A141247
%Y A100484 Adjacent sequences: A100481 A100482 A100483 this_sequence A100485 A100486 
               A100487
%K A100484 nonn
%O A100484 1,1
%A A100484 Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 22 2004
%E A100484 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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