A288449 Numbers k such that k!6 + 36 is prime, where k!6 is the sextuple factorial number (A085158 ).

1, 5, 7, 13, 17, 25, 29, 31, 55, 77, 119, 311, 373, 587, 1037, 1057, 1645, 2279, 2327, 2531, 2893, 2917, 3293, 3799, 9139, 14131, 14405, 15041, 24923, 26563, 48743

Offset

1,2

Comments

Corresponding primes are: 37, 41, 43, 127, 971, 43261, 623681, 1340011, 5745471106411, ...

a(32) > 50000.

Terms > 31 correspond to probable primes.

Links

Table of n, a(n) for n=1..31.

Henri & Renaud Lifchitz, PRP Records. Search for n!6+36.

Joe McLean, Interesting Sources of Probable Primes

OpenPFGW Project, Primality Tester

Example

13!6 + 36 = 13*7*1 + 36 = 127 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] + 36] &]

Crossrefs

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

Sequence in context: A163385 A368277 A358313 * A178218 A314323 A314324

Adjacent sequences: A288446 A288447 A288448 * A288450 A288451 A288452

Keyword

nonn,more

Author

Robert Price, Jun 09 2017

Status

approved