A032489 Numbers k such that 225*2^k+1 is prime.

3, 6, 8, 9, 12, 13, 14, 19, 22, 32, 35, 37, 80, 86, 102, 118, 135, 159, 205, 269, 430, 435, 535, 547, 830, 1020, 1030, 1079, 1089, 1112, 1189, 2244, 2397, 4497, 5888, 9549, 15942, 16855, 19736, 21936, 26744, 26926, 36744, 51142, 53155, 53532, 67017, 116067

Offset

1,1

Links

Jeppe Stig Nielsen, Table of n, a(n) for n = 1..69 (terms n = 1..67 from Robert Price)

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[225*2^# + 1] & ] (* Robert Price, Dec 19 2018 *)

Prog

(PARI) is(n)=ispseudoprime(225*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A191880 A084020 A167195 * A153769 A275608 A363758

Adjacent sequences: A032486 A032487 A032488 * A032490 A032491 A032492

Keyword

nonn,hard

Author

N. J. A. Sloane.

Extensions

a(47)-a(67) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 19 2018

Status

approved