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A289688
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Numbers k such that k!6 - 12 is prime, where k!6 is the sextuple factorial number (A085158).
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1
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11, 13, 23, 29, 35, 37, 49, 95, 97, 101, 113, 133, 137, 361, 401, 701, 1027, 1331, 2087, 2743, 7781, 9391, 12787, 12797, 16123, 17317, 21701, 49657, 64661, 72149, 86413
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OFFSET
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1,1
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COMMENTS
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Corresponding primes are: 43, 79, 21493, 623633, 21827563, 49579063, 104463111013, ...
a(32) > 10^5.
Terms > 49 correspond to probable primes.
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LINKS
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EXAMPLE
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13!6 - 12 = 13*7*1 - 12 = 79 is prime, so 13 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[8, 50000], PrimeQ[MultiFactorial[#, 6] - 12] &]
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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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