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A152099 Semiprimes based on powers of two and primes: a(n)=(2^Prime[n] - 1)*(2^Prime[n] + 1)=2^(2*Prime[n])-1. 1
15, 63, 1023, 16383, 4194303, 67108863, 17179869183, 274877906943, 70368744177663, 288230376151711743, 4611686018427387903, 18889465931478580854783, 4835703278458516698824703 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Idea resulted from seqfan posts by Artur Jasinski.

LINKS

Table of n, a(n) for n=1..13.

MATHEMATICA

Table[(2^Prime[n] - 1)*(2^Prime[n] + 1), {n, 1, 20}]

CROSSREFS

Sequence in context: A104473 A135972 A138104 * A119496 A044153 A044534

Adjacent sequences:  A152096 A152097 A152098 * A152100 A152101 A152102

KEYWORD

nonn

AUTHOR

Roger L. Bagula, Nov 24 2008

STATUS

approved

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Last modified March 29 02:19 EDT 2020. Contains 333104 sequences. (Running on oeis4.)