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A116213 (2^(2^(2^n))-1)/(2^(2^n)+1). 0
1, 3, 3855, 450552876409790643671482431940419874915447411150352389258589821042463539455 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

2^n+1 divides 2^(2^n)-1 iff n is a power of 2.

LINKS

Table of n, a(n) for n=0..3.

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

Adjacent sequences:  A116210 A116211 A116212 * A116214 A116215 A116216

KEYWORD

nonn

AUTHOR

Alexander Adamchuk, Apr 08 2007

STATUS

approved

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Last modified April 26 12:00 EDT 2019. Contains 322472 sequences. (Running on oeis4.)