A288450 - OEIS

A288450

Numbers k such that k!6 + 48 is prime, where k!6 is the sextuple factorial number (A085158 ).

5, 11, 13, 17, 19, 35, 43, 49, 67, 71, 73, 85, 103, 263, 293, 497, 529, 599, 905, 971, 1685, 2927, 3635, 3847, 4535, 8501, 38777

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Corresponding primes are: 53, 103, 139, 983, 1777, 21827623, 2131900273, 104463111073, ...

a(28) > 50000.

Terms > 49 correspond to probable primes.

LINKS

OpenPFGW Project, Primality Tester

EXAMPLE

11!6 + 48 = 11*5 + 48 = 103 is prime, so 11 is in the sequence.

MATHEMATICA

MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];

Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 48] &]

CROSSREFS

KEYWORD

nonn,more

AUTHOR

Robert Price, Jun 09 2017

STATUS

approved