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 A180627 Numbers k such that 6*k! - 1 is prime. 10
 0, 1, 2, 5, 8, 42, 318, 326, 1054, 2987 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Tested to 4400. - Robert G. Wilson v, Sep 28 2010 a(11) > 6300. - Jinyuan Wang, Feb 04 2020 LINKS Table of n, a(n) for n=1..10. Index entries for sequences related to numbers of primes of the form k*n!+-1 MATHEMATICA fQ[n_] := PrimeQ[6 n! - 1]; k = 0; lst = {}; While[k < 1501, If[ fQ@k, AppendTo[lst, k]; Print@k]; k++ ]; lst PROG (PARI) is(k) = ispseudoprime(6*k!-1); \\ Jinyuan Wang, Feb 04 2020 CROSSREFS Cf. A002982, A076133, A076134, A099350, A099351, A180628, A180630, A180630, A180631. Sequence in context: A214842 A299517 A268660 * A264860 A061354 A162709 Adjacent sequences: A180624 A180625 A180626 * A180628 A180629 A180630 KEYWORD nonn,more AUTHOR Robert G. Wilson v, Sep 13 2010 EXTENSIONS a(10) from Robert G. Wilson v, Sep 28 2010 STATUS approved

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Last modified June 25 03:44 EDT 2024. Contains 373694 sequences. (Running on oeis4.)