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A119573 Primes that have one of the forms 2^(2^n) + 1, 2^(2^n - 1) + 2^(2^(n + 1) - 1) + 1 or (2^(2^n) + 1 + 2^(2^(n + 1) - 1) + 1)/2. 0
3, 5, 7, 11, 17, 73, 137, 257, 65537 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..9.

MATHEMATICA

a = Union[Flatten[Table[{2^(2^n) + 1, 2^(2^n - 1) + 2^(2^(n + 1) - 1) + 1, (2^(2^n) + 1 + 2^(2^(n + 1) - 1) + 1)/2}, {n, 0, 10}]]] aout = Flatten[Table[If[PrimeQ[a[[n]]], a[[n]], {}], {n, 1, Length[a]}]]

CROSSREFS

Cf. A019434.

Sequence in context: A212912 A038944 A124081 * A001366 A093329 A246533

Adjacent sequences:  A119570 A119571 A119572 * A119574 A119575 A119576

KEYWORD

nonn

AUTHOR

Roger L. Bagula, May 31 2006

EXTENSIONS

Edited by N. J. A. Sloane, Jun 03 2006

STATUS

approved

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Last modified August 18 01:04 EDT 2019. Contains 326059 sequences. (Running on oeis4.)