A094630 Number of 3-uniform T_0-covers on n vertices.
1, 0, 0, 0, 5, 893, 1039947, 34351783511, 72057317345649377, 19342812465159881755696499, 1329227995591486918148744122456237749, 46768052394574271874021714673583968385714779097997, 1684996666696914425950059618212919561731019777110516294609942096153
Offset: 0
Keywords
Links
- Andrew Howroyd, Table of n, a(n) for n = 0..25
Programs
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PARI
seq(n)={Vec(serlaplace(exp(-x + x^2/2 + x^3/3 + O(x*x^n))*sum(k=0, n, 2^binomial(k, 3)*exp(-2^(k-1)*x^2 + O(x*x^(n-k)))*x^k/k!)))} \\ Andrew Howroyd, Jan 29 2020
Formula
E.g.f.: exp(-x+x^2/2+x^3/3)*Sum_{n>=0} 2^binomial(n, 3)*exp(-2^(n-1)*x^2)*x^n/n!.