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A076133 2*n! - 1 is a prime. 5
2, 3, 4, 5, 6, 7, 14, 15, 17, 22, 28, 91, 253, 257, 298, 659, 832, 866, 1849, 2495, 2716, 2773, 2831, 3364, 5264, 7429, 28539, 32123, 37868 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..29.

EXAMPLE

n=5 is here because 2*5!-1=239 is a prime.

MATHEMATICA

Select[Range[8000], PrimeQ[2 #! - 1] &] (* Vincenzo Librandi, Feb 20 2015 *)

PROG

(MAGMA) [n: n in [1..600] | IsPrime(2*Factorial(n)-1)]; // Vincenzo Librandi, Feb 20 2015

CROSSREFS

Cf. A051915, A076134, A051915, A076679.

Sequence in context: A319723 A271377 A066336 * A277908 A032862 A032886

Adjacent sequences:  A076130 A076131 A076132 * A076134 A076135 A076136

KEYWORD

nonn

AUTHOR

Phillip L. Poplin (plpoplin(AT)bellsouth.net), Oct 30 2002

EXTENSIONS

a(24)-a(29) from Serge Batalov, Feb 18 2015

STATUS

approved

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Last modified December 15 17:03 EST 2019. Contains 330000 sequences. (Running on oeis4.)