A355070 G.f.: Sum_{n>=0} a(n)*x^n/(n!*3^(n*(n-1)/2)) = log( Sum_{n>=0} x^n/(n!*3^(n*(n-1)/2)) ).
0, 1, -2, 28, -1808, 469072, -456745472, 1601325615808, -19650153075181568, 826737899840505194752, -117393483573257494026125312, 55564698792825562646890851908608, -86789641569440259960965030826164092928
Offset: 0
Keywords
Programs
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PARI
a(n) = n!*3^(n*(n-1)/2)*polcoef(log(sum(k=0, n, x^k/(k!*3^(k*(k-1)/2)))+x*O(x^n)), n);
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PARI
a_vector(n) = my(v=vector(n+1)); v[1]=0; for(i=1, n, v[i+1]=1-sum(j=1, i-1, 3^(j*(i-j))*binomial(i-1, j)*v[i-j+1])); v;
Formula
a(0) = 0; a(n) = 1 - Sum_{k=1..n-1} 3^(k*(n-k)) * binomial(n-1,k) * a(n-k).