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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 (list; graph; refs; listen; history; text; internal format)
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C. Caldwell and H. Dubner (Eds): The top ten prime numbers: from the unpublished collections of R. Ondrejka (May 2001), Table 21 F, p. 75.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

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Last modified September 28 05:33 EDT 2020. Contains 337392 sequences. (Running on oeis4.)