A093853 Number of 3-uniform T_0-hypergraphs without multiple edges on n vertices.

1, 1, 0, 0, 5, 918, 1045305, 34359063140, 72057592159917465, 19342813113675737866540892, 1329227995784915042800342940013202739, 46768052394588893381973221029683604571061797713236, 1684996666696914987166688353104182049991595860118136923187291272117

Offset

0,5

Links

Andrew Howroyd, Table of n, a(n) for n = 0..25

Formula

E.g.f.: (1+x)*exp(-x+x^2/2+x^3/3)*Sum_{n>=0} (2^binomial(n, 3)*exp(-2^(n-1)*x^2)*x^n/n!.

Prog

(PARI) seq(n)={Vec(serlaplace((1 + x)*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

Crossrefs

Cf. A094630, A094631.

Sequence in context: A284637 A173914 A015940 * A195627 A318066 A216375

Adjacent sequences: A093850 A093851 A093852 * A093854 A093855 A093856

Keyword

nonn

Author

Goran Kilibarda, Vladeta Jovovic, May 21 2004

Status

approved