A289825 Primes of the form k!3 - 59049, where k!3 is the triple factorial number (A007661).

1047511, 4129751, 24285271, 2504843351, 126757680265156951, 7368624314106569113540951, 38900816605808456499140951, 663800167477016615356604425212847831700575205814331164458540403251687739883519999999940951

Offset: 1

Author

Robert Price, Jul 12 2017

Keywords

• nonn

Links

• Robert Price, Table of n, a(n) for n = 1..9
• Henri & Renaud Lifchitz, PRP Records.Search for n!3-59049.
• Joe McLean, Interesting Sources of Probable Primes.
• OpenPFGW Project, Primality Tester.

Crossrefs

Cf. A007661, A265201.

Programs

Mathematica

MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
Select[Table[MultiFactorial[i, 3] - 59049, {i, 17, 100}], PrimeQ[#]&]

Formula

a(n) = A007661(A265201(n)) - 59049. - Elmo R. Oliveira, Feb 25 2025