A355085 E.g.f. A(x) satisfies A(x) = 1 + log(1+x) * A(3*x).
1, 1, 5, 128, 13572, 5462934, 7948602294, 40533916402440, 709019302729063320, 41863690463023189162224, 8239820880700969013925719856, 5352039696398504114334881521575792, 11377141201027327036487229661596883688304
Offset: 0
Keywords
Programs
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PARI
a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, (-1)^(j-1)*3^(i-j)*(j-1)!*binomial(i, j)*v[i-j+1])); v;
Formula
a(0) = 1; a(n) = Sum_{k=1..n} (-1)^(k-1) * 3^(n-k) * (k-1)! * binomial(n,k) * a(n-k).