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

Author

Reinhard Zumkeller, Nov 08 2004

Keywords

• nonn

Links

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

Crossrefs

Cf. A000123.

Programs

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 *)

Formula

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