

A166339


Numbers n such that Sum(n!/k!),k=0..n is prime.


0




OFFSET

1,2


COMMENTS

No further terms up to n=20000. The sequence a[n]=Sum(n!/k!),k=0..n is A000522.


LINKS

Table of n, a(n) for n=1..5.


FORMULA

n is an index of the sequence a[n]=Sum(n!/k!),k=0..n such that a[n] is prime.


EXAMPLE

For n=2, a[2]=5 which is a prime.


PROG

(PARI) a=1; for(n=1, 20000, a=n*a+1; if(ispseudoprime(a, 0), print("n="n)));


CROSSREFS

Cf. A000522 (corresponding sequence).
Sequence in context: A177188 A125635 A124361 * A024034 A101722 A004908
Adjacent sequences: A166336 A166337 A166338 * A166340 A166341 A166342


KEYWORD

nonn


AUTHOR

Mike Oakes, Oct 12 2009


STATUS

approved



