login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A331205 a(n) = least prime of the form 2^m - 2^n + 1. 3
2, 3, 5, 549755813881, 17, 97, 193, 140737488355201, 257, 7681, 15361, 134215681, 12289, 8380417, 114689 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

a(15) = 2^447 - 2^15 + 1 is too large to be represented in the data.

LINKS

Hugo Pfoertner, Table of n, a(n) for n = 0..62

EXAMPLE

See A331204.

PROG

(PARI) for(n=0, 14, for(m=n+1, oo, k=2^m-2^n+1; if(isprime(k), print1(k, ", "); break)))

CROSSREFS

Cf. A181692, A331204 (corresponding values of m).

Sequence in context: A305192 A141186 A078682 * A075174 A075176 A134972

Adjacent sequences:  A331202 A331203 A331204 * A331206 A331207 A331208

KEYWORD

nonn

AUTHOR

Hugo Pfoertner, Jan 12 2020

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 24 12:18 EST 2021. Contains 341569 sequences. (Running on oeis4.)