A099729 a(n) = a(n-1)^2 + a(floor(n/2))^2; a(0) = 1.

1, 2, 8, 68, 4688, 21977408, 483006462403088, 233295242723145661671791940368, 54426670277251448804881298598338033107084297639402489952768

Offset

0,2

Links

Table of n, a(n) for n=0..8.

Index entries for sequences of form a(n+1)=a(n)^2 + ...

Formula

a(n) ~ c^(2^n), where c = 1.6960426326108078452611100055735661068469295099996784988263600567400352165... . - Vaclav Kotesovec, Dec 18 2014

Mathematica

a = ConstantArray[0, 10]; a[[1]]=2; Do[a[[n]] = a[[n-1]]^2 + a[[Floor[n/2]]]^2, {n, 2, 10}]; Flatten[{1, a}] (* Vaclav Kotesovec, Dec 18 2014 *)

Crossrefs

Cf. A000123.

Sequence in context: A322495 A332637 A239843 * A373062 A123117 A330676

Adjacent sequences: A099726 A099727 A099728 * A099730 A099731 A099732

Keyword

nonn

Author

Reinhard Zumkeller, Nov 08 2004

Status

approved