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A116213
(2^(2^(2^n))-1)/(2^(2^n)+1).
0
1, 3, 3855, 450552876409790643671482431940419874915447411150352389258589821042463539455
OFFSET
0,2
COMMENTS
2^n+1 divides 2^(2^n)-1 iff n is a power of 2.
FORMULA
a(n) = (2^(2^(2^n))-1)/(2^(2^n)+1). a(n) = A051179(2^n)/A000215(n).
MATHEMATICA
Table[ (2^2^2^n - 1) / (2^2^n + 1), {n, 0, 3} ]
CROSSREFS
Cf. A000215 = Fermat numbers: 2^(2^n)+1. Cf. A051179 = 2^(2^n)-1.
Sequence in context: A226984 A196628 A089895 * A136544 A024048 A094319
KEYWORD
nonn
AUTHOR
Alexander Adamchuk, Apr 08 2007
STATUS
approved