A288448 Numbers k such that k!6 + 32 is prime, where k!6 is the sextuple factorial number (A085158 ).

5, 9, 17, 21, 29, 53, 57, 105, 111, 279, 303, 435, 483, 677, 1049, 1217, 1395, 9651, 26031, 31937

Offset: 1

Author

Robert Price, Jun 09 2017

Keywords

• nonn
• more

Comments

Corresponding primes are: 37, 59, 967, 8537, 623677, 2229272062357, 38661097149707, ...

a(21) > 50000.

Terms > 29 correspond to probable primes.

Examples

			17!6 + 32 = 17*11*5 + 32 = 967 is prime, so 17 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

Crossrefs

Cf. A007661, A037082, A084438, A123910, A242994.

Programs

Mathematica

MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 32] &]