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 A234854 E.g.f. satisfies: A'(x) = 1 + 4*A(x) + A(x)^2, where A(0)=0. 0

%I

%S 1,4,18,96,624,4896,45072,474624,5619456,73903104,1069106688,

%T 16872800256,288483876864,5311773904896,104789944829952,

%U 2205099306123264,49302137885884416,1167150882577711104,29165495002777387008,767163772371852066816,21188300138891474632704

%N E.g.f. satisfies: A'(x) = 1 + 4*A(x) + A(x)^2, where A(0)=0.

%F E.g.f.: Series_Reversion( Integral 1/(1 + 4*x + x^2) dx ).

%F E.g.f.: (2-sqrt(3))*(exp(2*sqrt(3)*x)-1)/(1 + (4*sqrt(3) - 7)*exp(2*sqrt(3)*x)). - _Vaclav Kotesovec_, Jan 13 2014

%F a(n) ~ n! * ((2*sqrt(3))/log(7+4*sqrt(3)))^(n+1). - _Vaclav Kotesovec_, Jan 13 2014

%F O.g.f.: x/(1-4*x - 1*2*x^2/(1-8*x - 2*3*x^2/(1-12*x - 3*4*x^2/(1-16*x - 4*5*x^2/(1-20*x - 5*6*x^2/(1- .../(1-4*n*x - n*(n+1)*x^2/(1- ...))))))) (continued fraction). - _Paul D. Hanna_, Sep 01 2014

%e E.g.f.: A(x) = x + 4*x^2/2! + 18*x^3/3! + 96*x^4/4! + 624*x^5/5! +...

%e Related series.

%e A(x)^2 = 2*x^2/2! + 24*x^3/3! + 240*x^4/4! + 2400*x^5/5! + 25488*x^6/6! +...

%t Rest[FullSimplify[CoefficientList[Series[(2-Sqrt[3])*(E^(2*Sqrt[3]*x)-1)/(1 + (4*Sqrt[3]-7)*E^(2*Sqrt[3]*x)),{x,0,15}],x]*Range[0,15]!]] (* _Vaclav Kotesovec_, Jan 13 2014 *)

%o (PARI) {a(n)=local(A=x);for(i=1,n,A=intformal(1+4*A+A^2 +x*O(x^n))); n!*polcoeff(A,n)}

%o for(n=1,25,print1(a(n),", "))

%o (PARI) {a(n)=local(A=serreverse(intformal(1/(1+4*x+x^2 +x*O(x^n))))); n!*polcoeff(A,n)}

%o for(n=1,25,print1(a(n),", "))

%K nonn

%O 1,2

%A _Paul D. Hanna_, Jan 09 2014

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Last modified August 13 14:01 EDT 2022. Contains 356091 sequences. (Running on oeis4.)