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A076189
Numbers k such that k!! + 2^4 is prime.
12
0, 1, 3, 5, 13, 17, 25, 27, 39, 45, 47, 53, 177, 217, 401, 637, 729, 787, 843, 3407, 8835, 10283, 14061, 21951
OFFSET
1,3
COMMENTS
a(25) > 50000. - Robert Price, Jan 19 2015
a(1)=0 since 0!!=1 and 1 + 2^4 = 17 is prime. - Robert Price, Jan 19 2015
LINKS
The OpenPFGW Project, Primality Tester
Henri & Renaud Lifchitz, PRP Records.
MAPLE
select(t -> isprime(doublefactorial(t)+16), [$0..1000]); # Robert Israel, Jan 19 2015
MATHEMATICA
lst={}; Do[If[PrimeQ[n!!+2^4], AppendTo[lst, n]], {n, 0, 50000}]; lst
CROSSREFS
Cf. A006882, A080778 and A076185, A076186, A076188, A076190, A076193, A076194, A076195, A076196, A076197 for other values of s in n!! + 2^s.
Sequence in context: A260191 A094745 A072742 * A291282 A073654 A060192
KEYWORD
nonn,more
AUTHOR
Zak Seidov, Nov 02 2002
EXTENSIONS
Edited and extended (n < 4096) by Hugo Pfoertner, Jun 19 2003
8835 from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
a(22)-a(24) from Robert Price, Jan 01 2013
a(1)=0 prepended by Robert Price, Jan 19 2015
STATUS
approved