A032477 - OEIS

A032477

Numbers k such that 201*2^k+1 is prime.

3, 4, 9, 60, 72, 75, 84, 348, 592, 1348, 1380, 1632, 1855, 2335, 4528, 9813, 17103, 28935, 34023, 100459, 243544, 281865, 371844, 648792, 812035, 886480, 2080464, 4146003

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

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..28.

Ray Ballinger, Proth Search Page

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

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

MATHEMATICA

Select[Range[1000], PrimeQ[201*2^# + 1] & ] (* Robert Price, Dec 19 2018 *)

PROG

(PARI) is(n)=ispseudoprime(201*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Sequence in context: A225467 A225473 A015240 * A073015 A364376 A240546

Adjacent sequences: A032474 A032475 A032476 * A032478 A032479 A032480

KEYWORD

nonn,hard,more

AUTHOR

N. J. A. Sloane.

EXTENSIONS

a(20)-a(26) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 19 2018

a(27) from Jeppe Stig Nielsen, May 30 2020

a(28) from Jeppe Stig Nielsen, Dec 23 2024

STATUS

approved