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A124381 O.g.f.: A(x) = Sum_{n>=0} x^n*Product_{k=0..n} (1 + k*(k+1)/2*x). 0

%I #4 Mar 30 2012 18:37:01

%S 1,1,2,5,14,48,181,772,3620,18511,102869,613584,3926895,26734671,

%T 193310243,1477081245,11896869336,100700815331,893438783126,

%U 8291513009130,80302486087937,810290260679230,8502192961792190

%N O.g.f.: A(x) = Sum_{n>=0} x^n*Product_{k=0..n} (1 + k*(k+1)/2*x).

%e A(x) = 1 + x*(1+x) + x^2*(1+x)*(1+3x) + x^3*(1+x)*(1+3x)*(1+6x) +...

%o (PARI) a(n)=polcoeff(sum(k=0,n,x^k*prod(j=0,k,1+j*(j+1)/2*x+x*O(x^n))),n)

%K nonn

%O 0,3

%A _Paul D. Hanna_, Oct 28 2006

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Last modified March 29 06:57 EDT 2024. Contains 371265 sequences. (Running on oeis4.)