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%I #30 Sep 16 2018 04:37:37
%S 0,1,3,5,13,17,25,27,39,45,47,53,177,217,401,637,729,787,843,3407,
%T 8835,10283,14061,21951
%N Numbers k such that k!! + 2^4 is prime.
%C a(25) > 50000. - _Robert Price_, Jan 19 2015
%C a(1)=0 since 0!!=1 and 1 + 2^4 = 17 is prime. - _Robert Price_, Jan 19 2015
%H The OpenPFGW Project, <a href="http://www.primeform.net/openpfgw/">Primality Tester</a>
%H Henri & Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=n%212%2B2%5E4&action=Search">PRP Records.</a>
%p select(t -> isprime(doublefactorial(t)+16), [$0..1000]); # _Robert Israel_, Jan 19 2015
%t lst={}; Do[If[PrimeQ[n!!+2^4], AppendTo[lst, n]], {n, 0, 50000}]; lst
%Y Cf. A006882, A080778 and A076185, A076186, A076188, A076190, A076193, A076194, A076195, A076196, A076197 for other values of s in n!! + 2^s.
%K nonn,more
%O 1,3
%A _Zak Seidov_, Nov 02 2002
%E Edited and extended (n < 4096) by _Hugo Pfoertner_, Jun 19 2003
%E 8835 from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
%E a(22)-a(24) from _Robert Price_, Jan 01 2013
%E a(1)=0 prepended by _Robert Price_, Jan 19 2015