OFFSET
1,1
COMMENTS
Corresponding primes are: 19, 47, 83, 397, 1721, 229627, 21827567, ...
a(48) > 10^5.
Terms > 99 correspond to probable primes.
LINKS
Henri & Renaud Lifchitz, PRP Records. Search for n!6-8.
Joe McLean, Interesting Sources of Probable Primes
OpenPFGW Project, Primality Tester
EXAMPLE
19!6 - 8 = 19*13*7 - 8 = 1721 is prime, so 19 is in the sequence.
MATHEMATICA
MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
Select[Range[8, 50000], PrimeQ[MultiFactorial[#, 6] - 8] &]
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert Price, Jul 09 2017
EXTENSIONS
a(47) from Robert Price, Aug 03 2018
STATUS
approved