A100339 Primes of the form 2^q + q where q is not a prime.

3, 521, 32783, 549755813927, 37778931862957161709643, 2417851639229258349412433

Offset

1,1

Comments

The next term is 2^735+735 = 18073..35103, 222 digits long.

Links

N. J. A. Sloane, Table of n, a(n) for n = 1..7

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

Cf. A057664, A081296, A129962.

Sequence in context: A155852 A003392 A133026 * A195626 A332153 A158247

Adjacent sequences: A100336 A100337 A100338 * A100340 A100341 A100342

Keyword

nonn

Author

Cino Hilliard, Jan 11 2005

Status

approved