A094144 Numbers n such that n!! - 2 is prime.

5, 7, 15, 17, 19, 51, 73, 89, 131, 153, 245, 333, 441, 463, 825, 1771, 2027, 9157, 10875, 20515

Offset

1,1

Comments

a(21) > 50000. - Robert Price, Apr 14 2015

Links

Table of n, a(n) for n=1..20.

C. K. Caldwell, The Prime Glossary, multifactorial prime

C. Caldwell and H. Dubner (Eds): The top ten prime numbers: from the unpublished collections of R. Ondrejka (May 2001), Table 21 F, p. 75

Ken Davis, Status of Search for Multifactorial Primes.

Joe McLean, Interesting Sources of Probable Primes

Mathematica

Select[Range[0, 50000], PrimeQ[#!! - 2] &] (* Robert Price, Apr 14 2014 *)

Crossrefs

Cf. A076185.

Sequence in context: A314357 A314358 A081965 * A314359 A314360 A314361

Adjacent sequences: A094141 A094142 A094143 * A094145 A094146 A094147

Keyword

nonn

Author

Lekraj Beedassy, May 04 2004

Extensions

Corrected by Robert G. Wilson v, May 05 2004

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

Status

approved