OFFSET
1,3
COMMENTS
a(n) <= n for all n. Thus a(n) = 0 is definite.
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 1..5000
EXAMPLE
7 + 1! = 8 is not prime.
7 + 2! = 9 is not prime.
7 + 3! = 13 is prime. Thus a(7) = 3.
PROG
(PARI)
a(n)=for(k=1, n, if(ispseudoprime(n+k!), return(k)))
vector(150, n, a(n))
CROSSREFS
KEYWORD
nonn
AUTHOR
Derek Orr, Jul 30 2014
STATUS
approved