A119571 a(n) = 2^(2^n - 1) + 2^(2^(n + 1) - 1) + 1.

4, 11, 137, 32897, 2147516417, 9223372039002259457, 170141183460469231740910675752738881537, 57896044618658097711785492504343953926805133516280751251460479307672448925697

Offset

0,1

Comments

Fermat-like sequence of powers of two.

Average of two consecutive Fermat numbers. - Juri-Stepan Gerasimov, Aug 26 2011

Links

Table of n, a(n) for n=0..7.

Formula

a(n) = A058891(n+1)+A058891(n+2)+1. - R. J. Mathar, Apr 22 2007

a(n) = (A000215(n)+A000215(n+1))/2. - Juri-Stepan Gerasimov, Aug 26 2011

Mathematica

aa = Table[2^(2^n - 1) + 2^(2^(n + 1) - 1) + 1, {n, 0, 10}]

Crossrefs

Sequence in context: A055979 A018242 A006248 * A089920 A303881 A305277

Adjacent sequences: A119568 A119569 A119570 * A119572 A119573 A119574

Keyword

nonn,easy

Author

Roger L. Bagula, May 31 2006

Extensions

Edited by N. J. A. Sloane, Jun 03 2006

Status

approved