OFFSET
1,1
COMMENTS
The next term is 2^735+735 = 18073..35103, 222 digits long.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..11 (terms 1..7 from N. J. A. Sloane)
FORMULA
EXAMPLE
For q = 9, 2^9+9 = 521 which is prime.
MATHEMATICA
Select[Table[If[!PrimeQ[n], 2^n+n, 0], {n, 1200}], PrimeQ] (* Vladimir Joseph Stephan Orlovsky, Feb 18 2011*)
PROG
(PARI) g1(p, n)=for(x=1, n, c=composite(x); y=p^c+c; if(gcd(y, c)==1, if(isprime(y), print1 (y", ")))) composite(n) = \ the n-th composite number { local(c, x); c=1; x=0; while(c <= n, x++; if(!isprime(x), c++); ); return(x) }
CROSSREFS
KEYWORD
nonn
AUTHOR
Cino Hilliard, Jan 11 2005
STATUS
approved