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 A290116 Primes of the form k! / 2 - 1. 1
 2, 11, 59, 359, 181439, 4111419327088961408862781439999999, 16726263306581903554085031026720375832575999999999 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Price, Table of n, a(n) for n = 1..7 Joe McLean, Interesting Sources of Probable Primes OpenPFGW Project, Primality Tester FORMULA a = (A082671(n)!-2)/2. EXAMPLE 6! / 2 - 1 = 359, which is prime, so 359 is in the sequence. 7! / 2 - 1 = 2519 = 11 * 229, so 2519 is not in the sequence. MATHEMATICA Select[Table[k! / 2 - 1, {k, 2, 100}], PrimeQ[#]&] CROSSREFS Cf. A082671, A139172. Sequence in context: A280674 A139172 A228868 * A251180 A286194 A164034 Adjacent sequences:  A290113 A290114 A290115 * A290117 A290118 A290119 KEYWORD nonn AUTHOR Robert Price, Jul 19 2017 STATUS approved

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Last modified September 21 11:09 EDT 2021. Contains 347597 sequences. (Running on oeis4.)