A284310 Numbers k such that k![14] + 2 is prime, where k![14] is the fourteen-fold multifactorial.

0, 1, 3, 5, 9, 11, 15, 17, 19, 21, 25, 27, 31, 33, 35, 45, 47, 67, 73, 87, 101, 107, 125, 153, 161, 179, 193, 229, 237, 247, 255, 277, 307, 333, 475, 495, 795, 799, 859, 861, 875, 915, 1023, 1077, 1115, 1175, 1221, 1227, 1245, 1345, 1687, 1923, 2337, 2595

Offset

1,3

Comments

a(108) > 10^5.

The first 17 primes associated with this sequence: 3, 3, 5, 7, 11, 13, 17, 53, 97, 149, 277, 353, 1583, 3137, 5147, 71147, 147347.

k = 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 32, 51, 72, 95, 120.

Links

Robert Price, Table of n, a(n) for n = 1..107

C. Caldwell and H. Dubner (Eds): The top ten prime numbers: from the unpublished collections of R. Ondrejka (May 2001), Table 21 F, p. 75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.

Mathematica

MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
Select[Range[0, 100000], PrimeQ[MultiFactorial[#, 14] + 2] &]

Crossrefs

Cf. A284190.

Sequence in context: A178442 A319986 A359408 * A109324 A356935 A190844

Adjacent sequences: A284307 A284308 A284309 * A284311 A284312 A284313

Keyword

nonn

Author

Robert Price, Mar 24 2017

Status

approved