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A238428 Expansion of F(x) where F(x) = 1 + x / (1 - x * F(x) - x^2 * F(x^2) ). 1
1, 1, 1, 3, 6, 17, 42, 118, 321, 920, 2626, 7679, 22554, 67115, 200883, 606238, 1839448, 5613892, 17211963, 53006846, 163866246, 508389780, 1582286912, 4939146731, 15459006948, 48505063741, 152539740067, 480726546083, 1517979996460, 4802074019769, 15217153748772, 48298352064093, 153526087484475 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
COMMENTS
What does this sequence count?
LINKS
FORMULA
a(n) ~ c * d^n / n^(3/2), where d = 3.3305741143240040687593..., c = 0.544842763137687191994... . - Vaclav Kotesovec, Aug 22 2014
PROG
(PARI)
N=66; R=O('x^N); x='x+R;
F = 1; for (k=1, N+1, F = 1 + x / (1 - x * F - x^2 * subst(F, 'x, 'x^2) ) + R; );
Vec(F)
CROSSREFS
Sequence in context: A089264 A121399 A212421 * A363387 A232771 A129905
KEYWORD
nonn
AUTHOR
Joerg Arndt, Feb 28 2014
STATUS
approved

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Last modified March 28 12:59 EDT 2024. Contains 371254 sequences. (Running on oeis4.)