A300408 Primes of the form 19*2^n + 1.

1217, 19457, 1337006139375617

Offset

1,1

Comments

Next term a(4) = 19*2^366 + 1 > 10^111.

For the corresponding exponents n see A032359.

Links

Table of n, a(n) for n=1..3.

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

Maple

a:=(n, k)->`if`(isprime(k*2^n+1), k*2^n+1, NULL):
seq(a(n, 19), n=1..366);

Prog

(GAP) Filtered(List([1..500], n->19*2^n + 1), IsPrime); # Muniru A Asiru, Mar 06 2018
(PARI) lista(nn) = {for(k=1, nn, if(ispseudoprime(p=19*2^k+1), print1(p, ", "))); } \\ Altug Alkan, Mar 29 2018

Crossrefs

Cf. A019434, A032359, A039687, A050527, A050528, A050529, A195745, A050526, A300406, A300407.

Sequence in context: A059669 A032628 A175964 * A252600 A293479 A031781

Adjacent sequences: A300405 A300406 A300407 * A300409 A300410 A300411

Keyword

nonn,less

Author

Martin Renner, Mar 05 2018

Status

approved