A283594 Numbers k such that k![12]+2 is prime, where k![12] is the twelve-fold multifactorial.

0, 1, 3, 5, 9, 11, 15, 21, 27, 29, 39, 99, 159, 213, 249, 351, 443, 489, 513, 563, 705, 1059, 1599, 1733, 2361, 3699, 4263, 4451, 4479, 5141, 5751, 7355, 7461, 8525, 8861, 18231, 19629, 23571, 41789, 76973, 86997, 93735, 98943

Offset: 1

Author

Robert Price, Mar 11 2017

Keywords

• nonn

Comments

a(44) > 10^5.

The first 12 primes associated with this sequence: 3, 3, 5, 7, 11, 13, 47, 191, 1217, 2467, 47387.

Links

• C. Caldwell and H. Dubner (Eds): The top ten prime numbers: from the unpublished collections of R. Ondrejka (May 2001), Table 21 F, p. 75
• Ken Davis, Status of Search for Multifactorial Primes.

Crossrefs

Cf. A076185, A085158, A094144, A204657.

Programs

Mathematica

MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 12] + 2] &]

Extensions

a(40)-a(43) from Robert Price, Mar 24 2017