A238431 Expansion of F(x) where F(x) = 1 + x / (1 - x * F(x^2)^2 ).

1, 1, 1, 1, 3, 5, 10, 19, 36, 69, 135, 258, 500, 963, 1862, 3592, 6940, 13393, 25869, 49939, 96437, 186190, 359531, 694176, 1340393, 2588071, 4997263, 9648958, 18630886, 35973552, 69460077, 134117616, 258962680, 500020761, 965470897, 1864189893, 3599491983, 6950118531, 13419713384, 25911601377

Offset

0,5

Comments

What does this sequence count?

a(n+1)/a(n) tends to 1.9308610132631268... - Vaclav Kotesovec, Feb 28 2014

Links

Table of n, a(n) for n=0..39.

Prog

(PARI)
N=66;  R=O('x^N);  x='x+R;
F = 1;  for (k=1, N+1, F = 1 + x / (1 - x * subst(F, 'x, 'x^2)^2 ) + R; );
Vec(F)

Crossrefs

Sequence in context: A261050 A158943 A133999 * A014610 A117591 A003055

Adjacent sequences: A238428 A238429 A238430 * A238432 A238433 A238434

Keyword

nonn

Author

Joerg Arndt, Feb 28 2014

Status

approved