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A050920 Cullen primes: primes of the form n*2^n+1. 6
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
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 A089418 A274981
KEYWORD
nonn,nice,bref
AUTHOR
N. J. A. Sloane, Dec 30 1999
STATUS
approved

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Last modified March 19 02:58 EDT 2024. Contains 370952 sequences. (Running on oeis4.)