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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
OFFSET
0,1
COMMENTS
Fermat-like sequence of powers of two.
Average of two consecutive Fermat numbers. - Juri-Stepan Gerasimov, Aug 26 2011.
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
KEYWORD
nonn
AUTHOR
Roger L. Bagula, May 31 2006
EXTENSIONS
Edited by N. J. A. Sloane, Jun 03 2006
STATUS
approved