login
A076186
Numbers n such that n!! + 2^2 is prime.
12
0, 1, 3, 5, 7, 11, 17, 29, 39, 43, 73, 93, 315, 549, 2059, 5543, 6937, 22819, 34523
OFFSET
1,3
COMMENTS
a(20) > 50000. - Robert Price, Feb 05 2015
Since 0!! is defined to be unity (A006882), 0!! + 2^2 = 5, which is prime. - Robert Price, Mar 22 2015
MATHEMATICA
Select[Range[0, 1000], PrimeQ[#!! + 4] &] (* Robert Price, Mar 22 2015 *)
CROSSREFS
Cf. A006882, A080778 and A076185, A076188, A076189, A076190, A076193, A076194, A076195, A076196, A076197 for other values of s in n!! + 2^s.
Sequence in context: A248714 A091567 A241896 * A092564 A068811 A145987
KEYWORD
nonn,more
AUTHOR
Zak Seidov, Nov 02 2002
EXTENSIONS
Edited and extended (n<4096) by Hugo Pfoertner, Jun 19 2003
6937 from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
Corrected by Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
a(18) = 22819 from Robert Price, Oct 04 2012
a(19) = 34523 from Robert Price, Feb 05 2015
a(1)=0 prepended by Robert Price, Mar 22 2015
STATUS
approved