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A119571 a(n) = 2^(2^n - 1) + 2^(2^(n + 1) - 1) + 1. 0
4, 11, 137, 32897, 2147516417, 9223372039002259457, 170141183460469231740910675752738881537, 57896044618658097711785492504343953926805133516280751251460479307672448925697 (list; graph; refs; listen; history; text; internal format)
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

AUTHOR

Roger L. Bagula, May 31 2006

EXTENSIONS

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

STATUS

approved

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Last modified January 28 00:32 EST 2020. Contains 331313 sequences. (Running on oeis4.)