OFFSET
0,1
COMMENTS
Is a(n)>=2 for all n>=0 and a(n)>=3 for all n>=2?
Also compare this with the conjecture on the fortunate numbers A005235.
Is the following true: for every m there is an N such that for all n>N a(n)>m?
There even seems to be the estimate a(n)>log(n+1)*sqrt(n+1)/2.
EXAMPLE
a(3)=7: The seven primes following 3!+1=7 are 11,13,17,19,23,29 and 31.
Subtracting 3!=6 from each of them gives 5,7,11,13,17,23 and 25.
The first six values are prime, while the seventh 25=5^2 is not.
MAPLE
a:=proc(n) option remember; local k:
for k from 1 while isprime((nextprime@@k)(n!+1)-n!) do od:
k; end;
CROSSREFS
KEYWORD
nonn
AUTHOR
Frederick Magata (frederick.magata(AT)web.de), May 13 2009
STATUS
approved