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 A090703 Numbers k such that k*k! + 1 is prime. 1
 1, 2, 3, 4, 5, 7, 12, 19, 23, 45, 58, 149, 151, 197, 682, 879, 1134, 1906, 6616, 10242 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS FORMULA a(n) = A049432(n)-1. EXAMPLE 3*3!+1 = 19 and 19 is prime, so 3 is a member. MATHEMATICA Do[If[PrimeQ[n*n! + 1], Print[n]], {n, 0, 2000}] (* Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), May 05 2006 *) PROG (PARI) isok(k) = ispseudoprime(k*k! + 1); \\ Altug Alkan, Mar 22 2018 CROSSREFS Cf. A049432. Sequence in context: A240732 A060437 A133428 * A137357 A100676 A193769 Adjacent sequences:  A090700 A090701 A090702 * A090704 A090705 A090706 KEYWORD nonn,more AUTHOR mohammed bouayoun (bouyao(AT)wanadoo.fr), Jan 15 2004 EXTENSIONS a(17) from Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), May 05 2006 a(18)-a(19) from Jason Earls, Jan 24 2008 a(20) from Seiichi Manyama (by using the data calculated by Donovan Johnson, Dec 18 2009), Mar 22 2018 STATUS approved

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Last modified February 16 02:39 EST 2019. Contains 320140 sequences. (Running on oeis4.)