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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 April 17 14:18 EDT 2021. Contains 343063 sequences. (Running on oeis4.)