OFFSET
1,2
COMMENTS
Corresponding primes are: 5, 7, 11, 31, 59, 409, 1733, 229639, 21827579, ...
a(45) > 50000.
Terms > 35 correspond to probable primes.
LINKS
Henri & Renaud Lifchitz, PRP Records. Search for n!6+4.
Joe McLean, Interesting Sources of Probable Primes
OpenPFGW Project, Primality Tester
EXAMPLE
11!6 + 4 = 11*5 + 4 = 59 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] + 4] &]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert Price, Jun 02 2017
STATUS
approved