

A329177


Numbers k such that k![4]  256 is prime, where k![4] = A007662(k) = quadruple factorial.


0



15, 17, 19, 21, 23, 25, 33, 39, 41, 43, 53, 63, 67, 73, 157, 167, 181, 195, 221, 327, 363, 419, 849, 861, 1233, 1265, 1599, 2413, 2515, 4009, 8291, 8475, 10685, 13957, 17453, 18409, 19117, 22739, 33313, 37861, 59703, 64983, 80697
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OFFSET

1,1


COMMENTS

a(44) > 10^5.
The first 5 primes associated with this sequence are: 3209, 9689, 65579, 208589, 1513949.


LINKS

Table of n, a(n) for n=1..43.
C. K. Caldwell, The Prime Glossary, multifactorial prime
C. Caldwell and H. Dubner (Eds): The top ten prime numbers: from the unpublished collections of R. Ondrejka (May 2001), Table 21 F, p. 75.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.
Joe McLean, Interesting Sources of Probable Primes


MATHEMATICA

MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n  k, k]];
Select[Range[1000], (x = MultiFactorial[#, 4]  256; x > 0 && PrimeQ[x]) &]


CROSSREFS

Cf. A007662, A283553.
Sequence in context: A077033 A043669 A043704 * A074748 A183981 A155111
Adjacent sequences: A329174 A329175 A329176 * A329178 A329179 A329180


KEYWORD

nonn


AUTHOR

Robert Price, Nov 07 2019


STATUS

approved



