A139065 - OEIS

A139065

Numbers k for which (7+k!)/7 is prime.

11, 15, 16, 25, 35, 59, 64, 68, 82, 121, 149, 238, 584, 912, 3349, 4111, 4324, 15314, 19944, 20658, 22740, 23364

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OFFSET

1,1

COMMENTS

For primes of the form (7+k!)/7, see A139064.

a(23) > 25000. - Robert Price, Nov 20 2016

LINKS

MATHEMATICA

a = {}; Do[If[PrimeQ[(n! + 7)/7], AppendTo[a, n]], {n, 1, 500}]; a

Select[Range[500], PrimeQ[(7+#!)/7]&] (* Harvey P. Dale, Sep 01 2014 *)

PROG

(PARI) for(k=7, 1e3, if(ispseudoprime(k!/7+1), print1(k", "))) \\ Charles R Greathouse IV, Jul 15 2011

CROSSREFS

Cf. k!/m-1 is a prime: A002982, A082671, A139056, A139199-A139205 (1<=m<=10).

KEYWORD

nonn,hard,more

AUTHOR

EXTENSIONS

More terms from Serge Batalov, Feb 18 2015

a(18)-a(22) from Robert Price, Nov 20 2016

STATUS

approved