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A288446
Numbers k such that k!6 + 24 is prime, where k!6 is the sextuple factorial number (A085158 ).
1
5, 7, 11, 19, 23, 29, 53, 67, 71, 79, 109, 121, 275, 707, 725, 1345, 1961, 2221, 2477, 2765, 5557, 5779, 7423, 11587, 22495, 25063, 28795, 43783
OFFSET
1,1
COMMENTS
Corresponding primes are: 29, 31, 79, 1753, 21529, 623669, 2229272062349, ...
a(29) > 50000.
Terms > 29 correspond to probable primes.
EXAMPLE
11!6 + 24 = 11*5 + 24 = 79 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] + 24] &]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert Price, Jun 09 2017
STATUS
approved