

A284132


Numbers k such that k![12]2 is prime, where k![12] is the twelvefold multifactorial.


2



4, 5, 7, 9, 13, 15, 17, 19, 23, 27, 41, 55, 63, 121, 177, 213, 219, 233, 241, 325, 335, 349, 357, 363, 373, 377, 421, 455, 503, 595, 775, 1053, 1297, 1447, 1501, 1765, 1871, 1915, 2111, 3039, 3801, 4993, 5273, 6753, 9247, 12063, 13433, 13663, 14783, 16295
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OFFSET

1,1


COMMENTS

a(64) > 100000.
The first 12 primes associated with this sequence: 2, 3, 5, 7, 11, 43, 83, 131, 251, 1213, 101063, 9750893.
k![12](0..20) = 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 28, 45, 64, 85, 108, 133, 160.


LINKS

Robert Price, Table of n, a(n) for n = 1..63
C. Caldwell and H. Dubner (Eds): The top ten prime numbers: from the unpublished collections of R. Ondrejka (May 2001), Table 21 F, p. 75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[2, 100000], PrimeQ[MultiFactorial[#, 12]  2] &]


CROSSREFS

Sequence in context: A032360 A117150 A239276 * A263427 A052147 A139690
Adjacent sequences: A284129 A284130 A284131 * A284133 A284134 A284135


KEYWORD

nonn


AUTHOR

Robert Price, Mar 20 2017


STATUS

approved



