A108272 Consider primes p and q such that p = 2^k + 21 and q = 2^(k+1) + 21 for some k; sequence gives values of p.

29, 37, 149, 32789, 2251799813685269

Offset

1,1

Comments

No additional terms up to k = 2000. - Harvey P. Dale, May 12 2019

Links

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

Mathematica

Select[Partition[2^Range[60]+21, 2, 1], AllTrue[#, PrimeQ]&][[All, 1]] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, May 12 2019 *)

Prog

(PARI) g(m, n, b) = { for(x=0, n, y=m+b^x+b%2; z=m+b^(x+1)+b%2; if(isprime(y)&isprime(z), print1(y", ") ) ) }

Crossrefs

Cf. A108273.

Sequence in context: A167470 A152865 A333422 * A121999 A069530 A259032

Adjacent sequences: A108269 A108270 A108271 * A108273 A108274 A108275

Keyword

nonn

Author

Cino Hilliard, Jun 29 2005

Status

approved