A116213 (2^(2^(2^n))-1)/(2^(2^n)+1).

1, 3, 3855, 450552876409790643671482431940419874915447411150352389258589821042463539455

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