A058384 Largest power of 2 which is a divisor of p(n)-1, where p(n) = n-th prime.

1, 2, 4, 2, 2, 4, 16, 2, 2, 4, 2, 4, 8, 2, 2, 4, 2, 4, 2, 2, 8, 2, 2, 8, 32, 4, 2, 2, 4, 16, 2, 2, 8, 2, 4, 2, 4, 2, 2, 4, 2, 4, 2, 64, 4, 2, 2, 2, 2, 4, 8, 2, 16, 2, 256, 2, 4, 2, 4, 8, 2, 4, 2, 2, 8, 4, 2, 16, 2, 4, 32, 2, 2, 4, 2, 2, 4, 4, 16, 8, 2, 4, 2, 16, 2, 2, 64, 8, 4, 2, 2, 2, 2, 2, 2, 2, 4, 8

Offset: 1

Author

Labos Elemer, Dec 20 2000

Keywords

• nonn

Examples

			n=25, p(25) - 1 = 97 - 1 = 96 = 32 * 3, so a(25) = 32.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A006093, A006519.

Programs

Mathematica

2^IntegerExponent[#,2]&/@(Prime[Range[100]]-1) (* Harvey P. Dale, Jan 17 2013 *)

Formula

a(n) = A006519(A006093(n)). - Amiram Eldar, Sep 23 2019

Extensions

Offset corrected by Amiram Eldar, Sep 23 2019