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A139201
Numbers k such that (k!-6)/6 is prime.
3
4, 5, 7, 8, 11, 14, 16, 17, 18, 20, 43, 50, 55, 59, 171, 461, 859, 2830, 3818, 5421, 5593, 10118, 10880, 24350
OFFSET
1,1
COMMENTS
a(25) > 25000. - Robert Price, Dec 15 2016
MAPLE
a:=proc(n) if isprime((1/6)*factorial(n)-1)=true then n else end if end proc: seq(a(n), n=4..500); # Emeric Deutsch, Apr 29 2008
MATHEMATICA
a = {}; Do[If[PrimeQ[(n! - 6)/6], Print[a]; AppendTo[a, n]], {n, 1, 300}]; a (* Artur Jasinski *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 11 2008
EXTENSIONS
2 more terms from Emeric Deutsch, Apr 29 2008
More terms from Serge Batalov, Feb 18 2015
a(22)-a(24) from Robert Price, Dec 15 2016
STATUS
approved