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A287844
Numbers k such that k!6 + 3 is prime, where k!6 is the sextuple factorial number (A085158 ).
1
2, 4, 8, 10, 14, 16, 20, 22, 26, 34, 70, 164, 346, 398, 902, 938, 1426, 1682, 1928, 3596, 3796, 15058, 25654, 37330
OFFSET
1,1
COMMENTS
Corresponding primes are: 5, 7, 19, 43, 227, 643, 4483, 14083, 116483, 13404163, ...
a(25) > 50000.
Terms > 34 correspond to probable primes.
EXAMPLE
10!6 + 3 = 10*4 + 3 = 43 is prime, so 10 is in the sequence.
MATHEMATICA
MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 3] &]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert Price, Jun 01 2017
STATUS
approved