OFFSET
1,1
COMMENTS
Corresponding primes are: 1453, 10133, 56053, 1104373, 24342133, 2504900213, 3091650738173813, ... .
a(35) > 50000.
Terms > 26 correspond to probable primes.
LINKS
Henri & Renaud Lifchitz, PRP Records. Search for n!3-2187.
Joe McLean, Interesting Sources of Probable Primes
OpenPFGW Project, Primality Tester
EXAMPLE
13!3 - 3^7 = 13*10*7*4 - 2187 = 1453 is prime, so 13 is in the sequence.
MATHEMATICA
MultiFactorial[n_, k_] := If[n < 1, 1, If[n < k + 1, n, n*MultiFactorial[n - k, k]]];
Select[Range[13, 50000], PrimeQ[MultiFactorial[#, 3] - 3^7] &]
Select[Range[12, 6000], PrimeQ[Times@@Range[#, 1, -3]-2187]&] (* The program generates the first 24 terms of the sequence. *) (* Harvey P. Dale, Aug 14 2024 *)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert Price, Jan 13 2016
STATUS
approved