A289910 The denominator of r(n), where r(n) = 1/r(n-2) + r(n-1); r(1)=r(2)=1/2.

2, 2, 2, 2, 10, 90, 4410, 2033010, 47753371890, 536047310324601810, 146146505822254040921594435610, 461461505298297622704608601547181743257756610890, 409066116871912908631970281597531260628466742447938742767153852110729821286410

Offset

1,1

Comments

It appears that the sequence is always in simplest terms when generated.

Links

Table of n, a(n) for n=1..13.

Mathematica

r[n_] := r[n] = If[n <= 2, 1/2, 1/r[n - 2] + r[n - 1]]; Denominator@ Array[r, 13] (* Michael De Vlieger, Jul 15 2017 *)

Crossrefs

Cf. A289909 (numerators).

Sequence in context: A217503 A165466 A175392 * A112727 A164918 A147822

Adjacent sequences: A289907 A289908 A289909 * A289911 A289912 A289913

Keyword

nonn,frac

Author

John Harmon, Jul 15 2017

Status

approved