A050895 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A050895

Numbers k such that 273*2^k-1 is prime.

2, 6, 10, 15, 22, 26, 31, 42, 47, 98, 107, 123, 126, 175, 178, 203, 223, 230, 239, 279, 371, 402, 519, 607, 755, 830, 871, 927, 980, 1527, 1770, 2007, 2218, 2247, 2250, 3982, 4367, 4510, 9716, 13018, 20906, 26340, 40186, 63332, 84599, 119743, 156155, 206118, 238687

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..49.

Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for k < 300

Wilfrid Keller, List of primes k.2^n - 1 for k < 300

Kosmaj, Riesel list k<300.

Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime

MATHEMATICA

Select[Range[1000], PrimeQ[273*2^# - 1] & ] (* Robert Price, Dec 30 2018 *)

PROG