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A200029 G.f. satisfies: A(x) = 1 + x*A(x)^3 + x^2*A(x)^2 + x^3*A(x). 2
1, 1, 4, 18, 89, 483, 2765, 16441, 100553, 628496, 3996864, 25778259, 168216339, 1108586737, 7367790912, 49326025289, 332342006775, 2251828394103, 15333892329935, 104883312564708, 720280904233625, 4964456716210287, 34329831032740121, 238109354053880367 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..23.

FORMULA

Recurrence: 2*n*(2*n+1)*(3887*n^4 - 54440*n^3 + 250111*n^2 - 457630*n + 282264)*a(n) = 3*(34983*n^6 - 524943*n^5 + 2755069*n^4 - 6525877*n^3 + 7248740*n^2 - 3486644*n + 563184)*a(n-1) + 9*(7774*n^6 - 128315*n^5 + 763466*n^4 - 2108189*n^3 + 2796852*n^2 - 1569116*n + 201744)*a(n-2) + (42757*n^6 - 769868*n^5 + 5072115*n^4 - 15417004*n^3 + 21905960*n^2 - 12286992*n + 1257984)*a(n-3) - 36*(11*n^2 - 51*n - 2)*(113*n^2 - 685*n + 924)*a(n-4) - 2*(27209*n^6 - 571543*n^5 + 4528416*n^4 - 16844723*n^3 + 29833927*n^2 - 22362054*n + 4746168)*a(n-5) - (n-7)*(38870*n^5 - 602705*n^4 + 3170125*n^3 - 6712006*n^2 + 5294904*n - 895104)*a(n-6) + 648*(n-8)*(3*n - 7)*(11*n^2 - 51*n - 2)*a(n-7) + 108*(n-9)*(n+4)*(11*n^2 - 51*n - 2)*a(n-8) + 3*(n - 10)*(n-7)*(3887*n^4 - 38892*n^3 + 110113*n^2 - 105180*n + 24192)*a(n-9). - Vaclav Kotesovec, Sep 11 2013

a(n) ~ c*d^n/n^(3/2), where d = 7.40643631692299994... is the root of the equation -3 + 10*d^3 + 14*d^4 - 11*d^6 - 18*d^7 - 27*d^8 + 4*d^9 = 0 and c = 0.268208461330470914429962064... - Vaclav Kotesovec, Sep 11 2013

EXAMPLE

G.f.: A(x) = 1 + x + 4*x^2 + 18*x^3 + 89*x^4 + 483*x^5 + 2765*x^6 +...

Related expansions:

A(x)^2 = 1 + 2*x + 9*x^2 + 44*x^3 + 230*x^4 + 1288*x^5 + 7532*x^6 +...

A(x)^3 = 1 + 3*x + 15*x^2 + 79*x^3 + 435*x^4 + 2517*x^5 + 15064*x^6 +...

MATHEMATICA

nmax=20; aa=ConstantArray[0, nmax]; aa[[1]]=1; Do[AGF=1+Sum[aa[[n]]*x^n, {n, 1, j-1}]+koef*x^j; sol=Solve[Coefficient[1 + x*AGF^3 + x^2*AGF^2 + x^3*AGF - AGF, x, j]==0, koef][[1]]; aa[[j]]=koef/.sol[[1]], {j, 2, nmax}]; Flatten[{1, aa}] (* Vaclav Kotesovec, Sep 11 2013 *)

PROG

(PARI) {a(n)=local(A=1+x); for(i=1, n, A=1+x*A^3+x^2*A^2+x^3*A^1+x*O(x^n)); polcoeff(A, n)}

CROSSREFS

Cf. A200028, A200030.

Sequence in context: A046984 A129323 A000305 * A020070 A197650 A036749

Adjacent sequences:  A200026 A200027 A200028 * A200030 A200031 A200032

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Nov 12 2011

STATUS

approved

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Last modified April 18 11:35 EDT 2014. Contains 240707 sequences.