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Search: id:A127955
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A127955 Composite numbers of the form (2^p+1)/3 where p is a prime. +0
13
178956971, 45812984491, 733007751851, 46912496118443, 3002399751580331, 192153584101141163, 49191317529892137643, 787061080478274202283, 3148244321913096809131, 3223802185639011132549803 (list; graph; listen)
OFFSET

1,1

COMMENT

If p-1 is squarefree, the terms are overpseudoprimes (see A141232). - Vladimir Shevelev (shevelev(AT)bgu.ac.il), Jul 15 2008

MATHEMATICA

a = {}; Do[c = (2^Prime[x] + 1)/3; If[PrimeQ[c] == False, AppendTo[a, c]], {x, 2, 30}]; a

CROSSREFS

Cf. A000979, A000978, A124400, A126614, A127956, A127957.

Sequence in context: A003843 A093047 A093046 this_sequence A047738 A079323 A061440

Adjacent sequences: A127952 A127953 A127954 this_sequence A127956 A127957 A127958

KEYWORD

nonn

AUTHOR

Artur Jasinski (grafix(AT)csl.pl), Feb 09 2007

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Last modified December 20 16:54 EST 2009. Contains 171081 sequences.


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