A329177 Numbers k such that k![4] - 256 is prime, where k![4] = A007662(k) = quadruple factorial.

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

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C. Caldwell and H. Dubner (Eds): The top ten prime numbers: from the unpublished collections of R. Ondrejka (May 2001), Table 21 F, p. 75.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]) &]
Select[Range[10, 1600], PrimeQ[Times@@Range[#, 1, -4]-256]&] (* The program generates the first 27 terms of the sequence. To generate more, increase the second Range constant but the program may take a long time to run. *) (* Harvey P. Dale, Aug 01 2022 *)

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