A289755 Primes of the form k!9-1, where k!9 is the nonuple factorial number (A114806).

2, 3, 5, 7, 89, 439, 1609, 4373, 22679, 5445439, 152681759, 17893715839, 101636305971199, 12652843234348799, 266565181393279999, 4929089879840974847999, 16401565050020468398079999, 2263415976902824638935039999, 1692607074564424130419507199999

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..41 (* Terms 1 through 33 from Robert Price *)

Henri & Renaud Lifchitz, PRP Records.Search for n!9-1.

Joe McLean, Interesting Sources of Probable Primes

OpenPFGW Project, Primality Tester

Mathematica

MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
Select[Table[MultiFactorial[i, 9] - 1, {i, 2, 100}], PrimeQ[#]&]
Select[Table[Times@@Range[n, 1, -9]-1, {n, 200}], PrimeQ] (* Harvey P. Dale, Sep 12 2019 *)

Crossrefs

Cf. A204659.

Sequence in context: A070275 A171042 A068827 * A318202 A076406 A171050

Adjacent sequences: A289752 A289753 A289754 * A289756 A289757 A289758

Keyword

nonn

Author

Robert Price, Jul 11 2017

Status

approved