A076197 Numbers k such that k!! + 2^10 is prime.

5, 7, 21, 33, 153, 167, 171, 391, 789, 1323, 2645, 8655, 10153, 39967, 45369, 47599

Offset: 1

Author

Zak Seidov, Nov 02 2002

Keywords

• nonn
• more

Comments

a(17) > 50000. - Robert Price, Feb 24 2015

Links

• Henri & Renaud Lifchitz, PRP Records.
• OpenPFGW Project, Primality Tester

Crossrefs

Cf. A006882.

Numbers k such that k!! + 2^s is prime: A080778 (s=0), A076185 (s=1), A076186 (s=2), A076188 (s=3), A076189 (s=4), A076190 (s=5), A076193 (s=6), A076194 (s=7), A076195 (s=8), A076196 (s=9).

Programs

Mathematica

lst={};Do[If[PrimeQ[n!!+2^10], (*Print[n];*)AppendTo[lst, n]], {n, 6!}];lst (* Vladimir Joseph Stephan Orlovsky, Aug 26 2008 *)

Python

from gmpy2 import is_prime
A076197_list, g, h = [], 1, 1024
for i in range(3,10**5,2):
    g *= i
    if is_prime(g+h):
        A076197_list.append(i) # Chai Wah Wu, May 31 2015

Extensions

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

8655 from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008

a(13) from Robert Price, Mar 10 2013

a(14)-a(16) from Robert Price, Feb 24 2015