

A116897


Numbers k such that k!  k!! + 1 is prime, where k!! denotes double factorial (A001147).


1




OFFSET

1,1


COMMENTS

Next term is greater than 3000.


LINKS

Table of n, a(n) for n=1..10.


EXAMPLE

6!  6!! + 1 = 673, which is prime.


MATHEMATICA

Select[Range[900], PrimeQ[#!#!!+1]&] (* Harvey P. Dale, Mar 27 2015 *)


CROSSREFS

Cf. A000142, A001147, A116896.
Sequence in context: A173180 A200077 A256137 * A293763 A246324 A280227
Adjacent sequences: A116894 A116895 A116896 * A116898 A116899 A116900


KEYWORD

hard,more,nonn


AUTHOR

Giovanni Resta, Mar 04 2006


STATUS

approved



