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A289756 Primes of the form k!8-1, where k!8 is the octuple factorial number (A114800). 1
2, 3, 5, 7, 19, 47, 83, 127, 359, 1847, 26879, 55439, 13366079, 188743679, 38761631999, 9033331507199, 3896394330931199, 152349556104345599, 5305528527460761599, 57299708096576225279999, 160680029832131217407999, 383414179456168545484799 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Henri & Renaud Lifchitz, PRP Records.Search for n!8-1.
OpenPFGW Project, Primality Tester
MATHEMATICA
MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
Select[Table[MultiFactorial[i, 8] - 1, {i, 2, 100}], PrimeQ[#]&]
CROSSREFS
Cf. A204662.
Sequence in context: A215156 A065724 A235620 * A236303 A117315 A158473
KEYWORD
nonn
AUTHOR
Robert Price, Jul 11 2017
STATUS
approved

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Last modified March 29 05:48 EDT 2024. Contains 371265 sequences. (Running on oeis4.)