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A188194 G.f. satisfies: A(x) = Sum_{n>=0} log(1 + 2^n*x*A(x)^2)^n/n!. 1
1, 2, 14, 168, 3756, 261560, 80733232, 96730287424, 412733638204832, 6222933783425122080, 334514554099356252794912, 64846889330532757107162199040, 45814974387230048629026769270192768 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..12.

FORMULA

G.f. A(x) satisfies:

(1) A(x) = Sum_{n>=0} C(2^n,n)*x^n*A(x)^(2n),

(2) A(x) = sqrt((1/x)*Series_Reversion(x/B(x)^2)),

(3) A(x) = B(x*A(x)^2) and B(x) = A(x/B(x)^2),

where B(x) = Sum_{n>=0} C(2^n,n)*x^n is the g.f. of A014070.

(4) A(x) = F(x*A(x)) and F(x) = A(x/F(x)), where F(x) is the g.f. of A188193.

EXAMPLE

G.f.: A(x) = 1 + 2*x + 14*x^2 + 168*x^3 + 3756*x^4 + 261560*x^5 +...

which equals the series:

A(x) = 1 + log(1+2*x*A(x)^2) + log(1+4*x*A(x)^2)^2/2! + log(1+8*x*A(x)^2)^3/3! +...

Let B(x) equal the g.f. of A014070, which begins:

B(x) = 1 + 2*x + 6*x^2 + 56*x^3 + 1820*x^4 +...+ C(2^n,n)*x^n +...

then B(x) = A(x/B(x)^2) and A(x) = B(x*A(x)^2), so that:

A(x) = 1 + 2*x*A(x)^2 + 6*x^2*A(x)^4 + 56*x^3*A(x)^6 + 1820*x^4*A(x)^8 +...+ C(2^n,n)*x^n*A(x)^(2n) +...

PROG

(PARI) {a(n)=local(A=1+x); for(i=1, n, A=sum(m=0, n, log(1+2^m*x*A^2+x*O(x^n))^m/m!)); polcoeff(A, n)}

CROSSREFS

Cf. A014070, A188193.

Sequence in context: A084946 A047055 A229257 * A046247 A141012 A235369

Adjacent sequences:  A188191 A188192 A188193 * A188195 A188196 A188197

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Mar 23 2011

STATUS

approved

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Last modified September 20 05:37 EDT 2021. Contains 347577 sequences. (Running on oeis4.)