A127962 Binary expansion of A000979(n).

11, 1011, 101011, 1010101011, 101010101011, 1010101010101011, 101010101010101011, 1010101010101010101011, 101010101010101010101010101011, 101010101010101010101010101010101010101011

Offset: 1

Author

Artur Jasinski, Feb 09 2007

Keywords

• nonn
• base

Links

• Amiram Eldar, Table of n, a(n) for n = 1..20

Crossrefs

Cf. A000978, A000979, A007088, A124400, A126614, A127936, A127955, A127956, A127957, A127958, A127961.

Programs

Mathematica

b[n_] := FromDigits[IntegerDigits[n, 2]]; b /@ Select[Table[(2^p + 1)/3, {p, Prime[Range[15]]}], PrimeQ] (* Amiram Eldar, Jul 23 2023 *)

Python

from gmpy2 import divexact
from sympy import prime, isprime
A127962 = [int(bin(p)[2:]) for p in (divexact(2**prime(n)+1,3) for n in range(2,10**2)) if isprime(p)] # Chai Wah Wu, Sep 04 2014

Formula

a(n) = A007088(A000979(n)). - Amiram Eldar, Jul 23 2023

Extensions

Edited by N. J. A. Sloane, Jun 11 2007