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A050920 Cullen primes: primes of the form n*2^n+1. 5
3, 393050634124102232869567034555427371542904833 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The next term is too large to display here, having 1423 digits. See A005849.

LINKS

Table of n, a(n) for n=1..2.

Ray Ballinger, Cullen Primes: Definition and Status

Chris K. Caldwell, Cullen Primes

Eric Weisstein's World of Mathematics, Cullen Number

FORMULA

a(n) = A002064(A005849(n)).

EXAMPLE

1 * 2^1 + 1 = 3, which is prime.

141 * 2^141 + 1 = 393050634124102232869567034555427371542904833, which is also prime.

The third Cullen prime is approximately 2.677114856136697933736444 * 10^1422.

MATHEMATICA

Select[Table[n * 2^n + 1, {n, 5000}], PrimeQ] (* Harvey P. Dale, Dec 14 2014 *)

CROSSREFS

See A005849 for the corresponding n.

Sequence in context: A068740 A058473 A115527 * A001231 A141150 A089418

Adjacent sequences:  A050917 A050918 A050919 * A050921 A050922 A050923

KEYWORD

nonn,nice,bref,changed

AUTHOR

N. J. A. Sloane, Dec 30 1999

STATUS

approved

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Last modified August 17 05:45 EDT 2017. Contains 290635 sequences.