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A288449
Numbers k such that k!6 + 36 is prime, where k!6 is the sextuple factorial number (A085158 ).
1
1, 5, 7, 13, 17, 25, 29, 31, 55, 77, 119, 311, 373, 587, 1037, 1057, 1645, 2279, 2327, 2531, 2893, 2917, 3293, 3799, 9139, 14131, 14405, 15041, 24923, 26563, 48743
OFFSET
1,2
COMMENTS
Corresponding primes are: 37, 41, 43, 127, 971, 43261, 623681, 1340011, 5745471106411, ...
a(32) > 50000.
Terms > 31 correspond to probable primes.
EXAMPLE
13!6 + 36 = 13*7*1 + 36 = 127 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] + 36] &]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert Price, Jun 09 2017
STATUS
approved