A288882 Primes of the form k!3 + 3^6, where k!3 is the triple factorial number (A007661).

733, 739, 757, 809, 1009, 1609, 13049, 210169, 81359229952729, 126757680265216729, 13106744139423334400729, 2295148179742698933452800729, 12931890526958090978845347074978621685760000729

Offset: 1

Author

Robert Price, Jun 18 2017

Keywords

• nonn

Links

• Robert Price, Table of n, a(n) for n = 1..18
• Henri and Renaud Lifchitz, PRP Records.Search for n!3+3^6.
• Joe McLean, Interesting Sources of Probable Primes.
• OpenPFGW Project, Primality Tester.

Crossrefs

Cf. A007661, A247467, A247867.

Programs

Mathematica

MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
Select[Table[MultiFactorial[i, 3] + 3^6, {i, 0, 100}], PrimeQ[#]&]

Formula

a(n) = 729 + A007661(A247467(n)). - Elmo R. Oliveira, Apr 20 2025