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A288155
Numbers k such that k!6 + 12 is prime, where k!6 is the sextuple factorial number (A085158 ).
1
0, 1, 5, 7, 11, 13, 17, 19, 23, 25, 41, 67, 71, 101, 109, 151, 163, 181, 233, 241, 265, 355, 433, 563, 767, 997, 1465, 1681, 1861, 1913, 2411, 2539, 2777, 13433, 22355, 30895, 44605
OFFSET
1,3
COMMENTS
Corresponding primes are: 13, 13, 17, 19, 67, 103, 947, 1741, 21517, 43237, 894930587, ...
a(37) > 50000.
Terms > 41 correspond to probable primes.
EXAMPLE
11!6 + 12 = 11*5 + 12 = 67 is prime, so 11 is in the sequence.
MATHEMATICA
MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 12] &]
Select[Range[0, 45000], PrimeQ[Times @@ Range[#, 1, -6] + 12] &] (* Harvey P. Dale, Jul 09 2020 *)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert Price, Jun 05 2017
STATUS
approved