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A153395 G.f.: A(x) = F(x*G(x)) where F(x) = G(x/F(x)^2) = 1 + x*F(x)^2 is the g.f. of A000108 (Catalan) and G(x) = F(x*G(x)^2) = 1 + x*G(x)^4 is the g.f. of A002293. 2
1, 1, 3, 13, 69, 417, 2754, 19373, 142732, 1088875, 8533278, 68308641, 556242792, 4593529882, 38380159009, 323860968709, 2756019889146, 23625552635184, 203823793118268, 1768357487401595, 15418860927887232, 135042445950316514 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

This appears to be the same as the sequence in row 1 of Fig. 21 of Novelli-Thibon 2014. - N. J. A. Sloane, Jun 14 2014

LINKS

Table of n, a(n) for n=0..21.

J.-C. Novelli, J.-Y. Thibon, Hopf Algebras of m-permutations,(m+1)-ary trees, and m-parking functions, arXiv preprint arXiv:1403.5962, 2014.

FORMULA

a(n) = Sum_{k=0..n} C(2k+1,k)/(2k+1) * C(4n-3k,n-k)*k/(4n-3k) for n>0 with a(0)=1.

G.f. satisfies: A(x) = 1 + x*G(x)*A(x)^2 where G(x) is the g.f. of A002293.

G.f. satisfies: A(x/F(x)^2) = F(x/F(x)) where F(x) is the g.f. of A000108.

G.f. satisfies: A(x/H(x)) = F(x) where H(x) = 1 + x*H(x)^3 is the g.f. of A001764 and F(x) is the g.f. of A000108.

EXAMPLE

G.f.: A(x) = F(x*G(x)) = 1 + x + 3*x^2 + 13*x^3 + 69*x^4 +... where

F(x) = 1 + x + 2*x^2 + 5*x^3 + 14*x^4 + 42*x^5 + 132*x^6 +...

F(x)^2 = 1 + 2*x + 5*x^2 + 14*x^3 + 42*x^4 + 132*x^5 + 429*x^6 +...

G(x) = 1 + x + 4*x^2 + 22*x^3 + 140*x^4 + 969*x^5 + 7084*x^6 +...

G(x)^2 = 1 + 2*x + 9*x^2 + 52*x^3 + 340*x^4 + 2394*x^5 +...

G(x)^3 = 1 + 3*x + 15*x^2 + 91*x^3 + 612*x^4 + 4389*x^5 +...

G(x)^4 = 1 + 4*x + 22*x^2 + 140*x^3 + 969*x^4 + 7084*x^5 +...

A(x)^2 = 1 + 2*x + 7*x^2 + 32*x^3 + 173*x^4 + 1050*x^5 +...

G(x)*A(x)^2 = 1 + 3*x + 13*x^2 + 69*x^3 + 417*x^4 + 2754*x^5 +...

MATHEMATICA

nmax = 21;

G[_] = 0;

Do[G[x_] = 1 + x*G[x]^4 + O[x]^nmax, nmax];

F[x_] = Sum[CatalanNumber[n] x^n, {n, 0, nmax}];

A[x_] = F[x G[x]];

CoefficientList[A[x], x] (* Jean-Fran├žois Alcover, Sep 09 2018 *)

PROG

(PARI) {a(n)=if(n==0, 1, sum(k=0, n, binomial(2*k+1, k)/(2*k+1)*binomial(4*(n-k)+k, n-k)*k/(4*(n-k)+k)))}

CROSSREFS

Cf. A000108, A001764, A002293; A153394, A153396.

Sequence in context: A284719 A128079 A074534 * A243688 A088714 A067145

Adjacent sequences:  A153392 A153393 A153394 * A153396 A153397 A153398

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jan 15 2009

STATUS

approved

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Last modified May 21 11:35 EDT 2019. Contains 323443 sequences. (Running on oeis4.)