

A215913


Primes of the form 2*!n1.


0




OFFSET

0,1


COMMENTS

!n is a subfactorial number (A000166). The corresponding n are {3, 4, 12, 13, 97,...}.


LINKS

Table of n, a(n) for n=0..3.


EXAMPLE

The prime 17 = 2* !4  1 = 2*9 1 is in the sequence.


MAPLE

with(numtheory): f:=n>sum(n!*(((1)^k)*1/k!), k=0..n):for n from 1 to 150 do: if type(2*f(n)1, prime) = true then printf(`%d, `, 2*f(n)1):else fi:od:


MATHEMATICA

a={}; Do[p= 2* Subfactorial[n]1; If[PrimeQ[p], AppendTo[a, p]], {n, 0, 800}]; Print[a];


CROSSREFS

Cf. A006882, A215912.
Sequence in context: A351590 A175984 A051710 * A162713 A161473 A208493
Adjacent sequences: A215910 A215911 A215912 * A215914 A215915 A215916


KEYWORD

nonn


AUTHOR

Michel Lagneau, Aug 26 2012


STATUS

approved



