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A247466
Numbers n such that n!3 - 3^6 is prime.
1
11, 26, 37, 38, 40, 41, 62, 131, 211, 212, 251, 272, 284, 383, 427, 538, 590, 860, 1087, 1280, 1826, 1835, 1895, 2276, 2524, 2872, 3769, 3878, 4334, 5704, 14332, 23386, 42694
OFFSET
1,1
COMMENTS
Large terms correspond to probable primes.
a(34) > 50000.
LINKS
Henri & Renaud Lifchitz, PRP Records. Search for n!3-729
OpenPFGW Project, Primality Tester
Eric Weisstein's World of Mathematics, Multifactorial
EXAMPLE
11!3-729 = 11*8*5*2-729= 151 is prime, so 11 is in the sequence.
MATHEMATICA
MultiFactorial[n_, k_] := If[n < 1, 1, If[n < k + 1, n, n*MultiFactorial[n - k, k]]];
lst={}; Do[If[PrimeQ[MultiFactorial[n, 3] - 729], AppendTo[lst, n]], {n, 100}]; lst
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert Price, Sep 17 2014
STATUS
approved