A076188 Numbers k such that k!! + 2^3 is prime.

3, 5, 7, 9, 15, 17, 25, 41, 63, 79, 91, 103, 299, 341, 431, 445, 465, 519, 1251, 2469, 2507, 2549, 6817, 8519, 18983, 38715

Offset

1,1

Comments

a(27) > 50000. - Robert Price, Jan 06 2015

Links

Table of n, a(n) for n=1..26.

Henri & Renaud Lifchitz, PRP Records.

OpenPFGW Project, Primality Tester

Mathematica

lst={}; Do[If[PrimeQ[n!!+2^3], AppendTo[lst, n]], {n, 0, 50000}]; lst
Select[Range[40000], PrimeQ[#!!+8]&] (* Harvey P. Dale, May 28 2021 *)

Crossrefs

Cf. A006882, A080778 and A076185, A076186, A076189, A076190, A076193, A076194, A076195, A076196, A076197 for other values of s in n!!+2^s.

Sequence in context: A329419 A235264 A064896 * A265852 A335132 A343727

Adjacent sequences: A076185 A076186 A076187 * A076189 A076190 A076191

Keyword

nonn,more

Author

Zak Seidov, Nov 02 2002

Extensions

Edited and extended (n<4096) by Hugo Pfoertner, Jun 19 2003

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008

a(25) from Robert Price, Nov 01 2012

a(26) from Robert Price, Jan 06 2015

Status

approved