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

1,2

Links

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

Formula

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

Example

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

Mathematica

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

Crossrefs

Cf. A006093, A006519.

Sequence in context: A294354 A144049 A368435 * A255671 A330590 A055097

Adjacent sequences: A058381 A058382 A058383 * A058385 A058386 A058387

Keyword

nonn

Author

Labos Elemer, Dec 20 2000

Extensions

Offset corrected by Amiram Eldar, Sep 23 2019

Status

approved