A384697 Primes of the form floor(2^k / 5).

3, 409, 6553, 1677721, 6871947673, 472236648286964521369, 7922816251426433759354395033, 2451992865385422173373355243440494693789982595493763481

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..15

Formula

a(n) = floor(2^A383966(n)/5).

Mathematica

Select[Table[Quotient[(2^n), 5], {n, 1, 250}], PrimeQ]

Prog

(Magma) [ a: k in [0..500] | IsPrime(a) where a is 2^k div 5 ];

Crossrefs

Cf. A383966 (corresponding k).

Sequence in context: A377032 A330014 A305664 * A152517 A333134 A366355

Adjacent sequences: A384694 A384695 A384696 * A384698 A384699 A384700

Keyword

nonn

Author

Vincenzo Librandi, Jun 07 2025

Status

approved