A289824 Primes of the form k!3 - 19683, where k!3 is the triple factorial number (A007661).

38557, 189757, 17961239276317, 3091650738156317, 2576442067869429740317, 142299187144047333874073580317, 3304568487306325139410771509247980317, 1745488670154377397414943478973600699284193279980317, 32574963783105296932155733349839640225269943165384327692287999999980317

Offset

1,1

Links

Robert Price, Table of n, a(n) for n = 1..14

Henri and Renaud Lifchitz, PRP Records.Search for n!3-19683.

Joe McLean, Interesting Sources of Probable Primes.

OpenPFGW Project, Primality Tester.

Formula

a(n) = A007661(A267029(n)) - 19683. - Elmo R. Oliveira, Feb 25 2025

Mathematica

MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
Select[Table[MultiFactorial[i, 3] - 19683, {i, 15, 100}], PrimeQ[#]&]
Select[Table[Times@@Range[n, 1, -3]-19683, {n, 15, 100}], PrimeQ] (* Harvey P. Dale, Dec 14 2019 *)

Crossrefs

Cf. A007661, A267029.

Sequence in context: A250712 A362217 A330427 * A321494 A252103 A074484

Adjacent sequences: A289821 A289822 A289823 * A289825 A289826 A289827

Keyword

nonn,changed

Author

Robert Price, Jul 12 2017

Status

approved