A089535 Semiprimes of the form 2^k + k.

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

Offset

1,1

Links

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

Formula

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

Mathematica

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

Crossrefs

Intersection of A001358 and A006127.

Cf. A085745, A089536, A089537, 129962.

Sequence in context: A209520 A279440 A004817 * A059081 A373235 A226461

Adjacent sequences: A089532 A089533 A089534 * A089536 A089537 A089538

Keyword

nonn

Author

Ray Chandler, Nov 08 2003

Extensions

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

Status

approved