A289699 Numbers k such that k!6 - 32 is prime, where k!6 is the sextuple factorial number (A085158).
11, 13, 15, 19, 33, 35, 39, 59, 63, 75, 105, 143, 187, 213, 271, 307, 431, 549, 1211, 1597, 1879, 2025, 3085, 5995, 5997, 6697, 6795, 10543, 21515, 25811, 34345, 57561, 70797, 71671
Offset: 1
Examples
15!6 - 32 = 15*9*3 - 32 = 373 is prime, so 15 is in the sequence.
Links
- Henri & Renaud Lifchitz, PRP Records. Search for n!6-32.
- Joe McLean, Interesting Sources of Probable Primes
- OpenPFGW Project, Primality Tester
Programs
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Mathematica
MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]]; Select[Range[10, 50000], PrimeQ[MultiFactorial[#, 6] - 32] &]
Extensions
a(32)-a(34) from Robert Price, Aug 04 2018
Comments