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A279646
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Numbers k such that k!6 - 3 is prime, where k!6 is the sextuple factorial number (A085158).
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1
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5, 6, 8, 10, 68, 82, 92, 98, 118, 286, 796, 878, 1360, 1502, 1516, 1568, 1646, 3628, 3716, 4048, 7982, 12776, 18070, 20594, 29902, 39632, 52988, 53864, 55610, 67448, 85402, 89762
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OFFSET
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1,1
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COMMENTS
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Corresponding primes are: 2, 3, 13, 37, 73569236156415997, ...
a(33) > 10^5.
Terms > 10 correspond to probable primes.
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LINKS
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EXAMPLE
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10!6 - 3 = 10*4 - 3 = 37 is prime, so 10 is in the sequence.
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MATHEMATICA
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MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
Select[Range[4, 50000], PrimeQ[MultiFactorial[#, 6] - 3] &]
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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