A152099 a(n) = (2^prime(n) - 1)*(2^prime(n) + 1) = 2^(2*prime(n)) - 1.

15, 63, 1023, 16383, 4194303, 67108863, 17179869183, 274877906943, 70368744177663, 288230376151711743, 4611686018427387903, 18889465931478580854783, 4835703278458516698824703, 77371252455336267181195263, 19807040628566084398385987583

Offset: 1

Author

Roger L. Bagula, Nov 24 2008

Keywords

• nonn

Comments

Idea resulted from seqfan posts by Artur Jasinski.

Crossrefs

Cf. A000040, A000302, A001348, A034785, A098640.

Programs

Mathematica

Table[(2^Prime[n] - 1)*(2^Prime[n] + 1), {n, 1, 20}]

Python

from sympy import prime
def A152099(n): return (1<<(prime(n)<<1))-1 # Chai Wah Wu, Jun 26 2023

Formula

a(n) = A001348(n) * A098640(n).

a(n) = A034785(n)^2 - 1.

a(n) = A000302(A000040(n)) - 1.