A259045 Numbers n such that n!! - 2^6 is prime.

7, 9, 11, 17, 21, 27, 29, 39, 43, 45, 67, 145, 173, 613, 833, 1449, 1703, 1719, 2673, 19661, 36095, 37837, 37845

Offset: 1

Author

Robert Price, Jun 17 2015

Keywords

• nonn
• hard
• more

Comments

a(24) > 50000.

Links

• C. K. Caldwell, The Prime Glossary, multifactorial prime
• Joe McLean, Interesting Sources of Probable Primes

Crossrefs

Cf. A007749, A094144, A123910, A257864 (other forms of n!!-2^k)

Cf. A080778, A076185, A076186, A076188, A076189, A076190, A076193, A076194, A076195, A076196, A076197 (other forms of n!!+2^k)

Programs

Mathematica

Select[Range[0, 50000], #!! - 64 > 0 && PrimeQ[#!! - 64] &]
Select[Range[4, 6000], PrimeQ[#!! - 64] &] (* Vincenzo Librandi, Jun 18 2015 *)