

A080778


Double factorial primes; values for which n!!+1 is prime.


23




OFFSET

1,3


COMMENTS

Numbers n such that A006882(n)+1 is prime.


LINKS

Table of n, a(n) for n=1..9.
Ken Davis, Status of Search for Multifactorial Primes.
Ken Davis, Results for n!2+1.
Eric Weisstein's World of Mathematics, Double Factorial Prime
Eric Weisstein's World of Mathematics, Integer Sequence Primes


CROSSREFS

Cf. A006882.
Sequence in context: A196290 A182446 A218436 * A007513 A283756 A071613
Adjacent sequences: A080775 A080776 A080777 * A080779 A080780 A080781


KEYWORD

hard,nonn


AUTHOR

Steven Harvey, Mar 11 2003


EXTENSIONS

a(7) from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
a(8) from Sou Fukui, Jun 05 2015
a(9) from Sou Fukui, Jan 17 2017


STATUS

approved



