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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 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 A089418 A274981 Adjacent sequences:  A050917 A050918 A050919 * A050921 A050922 A050923 KEYWORD nonn,nice,bref AUTHOR N. J. A. Sloane, Dec 30 1999 STATUS approved

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Last modified December 12 19:33 EST 2018. Contains 318081 sequences. (Running on oeis4.)