A089535 Semiprimes of the form 2^k + k.

6, 2059, 8388631, 17179869218, 576460752303423547, 590295810358705651781, 154742504910672534362390615, 39614081257132168796771975263, 664613997892457936451903530140172407, 10633823966279326983230456482242756731, 680564733841876926926749214863536423041

Offset: 1

Author

Ray Chandler, Nov 08 2003

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..26

Crossrefs

Intersection of A001358 and A006127.

Cf. A085745, A089536, A089537, 129962.

Programs

Mathematica

Select[Table[2^k+k,{k,200}],PrimeOmega[#]==2&] (* Harvey P. Dale, Aug 11 2024 *)

Formula

a(n) = 2^A085745(n) + A085745(n).

Extensions

a(10)-a(11) from Jinyuan Wang, Jul 30 2021