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A219119 E.g.f.: Sum_{n>=0} log(1 + x/(1-x)^n)^n / n!. 0

%I

%S 1,1,2,12,96,1000,13500,221718,4301808,97747200,2555001360,

%T 75526842600,2503943418240,92407030642056,3759862792921872,

%U 167429488088545200,8120958429706093440,426777425467443381120,24161214872571127574400,1467122583066982481802816

%N E.g.f.: Sum_{n>=0} log(1 + x/(1-x)^n)^n / n!.

%F E.g.f.: Sum_{n>=0} binomial(1/(1-x)^n, n) * x^n.

%F E.g.f.: Sum_{n>=0} x^n/n! * Product_{k=0..n-1} (1/(1-x)^n - k).

%F E.g.f.: Sum_{n>=0} x^n/n! * Sum_{k=0..n} Stirling1(n,k) / (1-x)^(n*k).

%e E.g.f.: A(x) = 1 + x + 2*x^2/2! + 12*x^3/3! + 96*x^4/4! + 1000*x^5/5! +...

%e where the g.f. satisfies the identities:

%e A(x) = 1 + log(1+x/(1-x)) + log(1+x/(1-x)^2)^2/2! + log(1+x/(1-x)^3)^3/3! + log(1+x/(1-x)^4)^4/4! + log(1+x/(1-5*x)^5)^5/5! +...

%e A(x) = 1 + binomial(1/(1-x),1)*x + binomial(1/(1-x)^2,2)*x^2 + binomial(1/(1-x)^3,3)*x^3 + binomial(1/(1-x)^4,4)*x^4 + binomial(1/(1-x)^5,5)*x^5 +...

%e A(x) = 1 + x/(1-x) + x^2/(1-x)^4*(1-(1-x)^2)/2! + x^3/(1-x)^9*(1-(1-x)^3)*(1-2*(1-x)^3)/3! + x^4/(1-x)^16*(1-(1-x)^4)*(1-2*(1-x)^4)*(1-3*(1-x)^4)/4! +...

%o (PARI) {a(n)=n!*polcoeff(sum(m=0,n,log(1+x/(1-x+x*O(x^n))^m)^m/m!),n)}

%o (PARI) {a(n)=n!*polcoeff(sum(m=0,n,binomial(1/(1-x+x*O(x^n))^m,m)*x^m),n)}

%o for(n=0,30,print1(a(n),", "))

%o (PARI) {a(n)=n!*polcoeff(sum(m=0,n, x^m/m!*prod(k=0,m-1, (1/(1-x)^m-k+x*O(x^n)))),n)}

%o (PARI) {Stirling1(n, k)=n!*polcoeff(binomial(x, n), k)}

%o {a(n)=local(A=1+x); A=sum(m=0, n, sum(k=0, m, Stirling1(m, k)/(1-x+x*O(x^n))^(m*k))*x^m/m!); n!*polcoeff(A, n)}

%o for(n=0, 30, print1(a(n), ", "))

%Y Cf. A216839.

%K nonn

%O 0,3

%A _Paul D. Hanna_, Nov 13 2012

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Last modified June 23 12:05 EDT 2021. Contains 345401 sequences. (Running on oeis4.)