A094630 -id:A094630 - cp's OEIS frontend

A094631 Number of n-block 3-uniform T_0-covers.

1, 0, 0, 184, 16936, 2711904, 675457000, 232383728378, 105676839790294, 61466235823794521, 44524673319233300950, 39314601406037457009543, 41574584860907056125473119, 51879840704758774687928224799, 75441055286834286248687362255451, 126462548502721304612260672370098185

Offset: 0

Goran Kilibarda, Vladeta Jovovic, May 15 2004

nonn

a(n) is the number of binary matrices with n distinct columns and any number of distinct nonzero rows with 3 ones in every column and columns in decreasing lexicographic order. - Andrew Howroyd, Jan 25 2020

Andrew Howroyd, Table of n, a(n) for n = 0..100

Row n=3 of A331569.

Cf. A094630, A059530, A060070.

Terms a(11) and beyond from Andrew Howroyd, Jan 25 2020

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

Original entry on oeis.org

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

Offset: 0

Goran Kilibarda and Vladeta Jovovic, May 21 2004

nonn

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

Cf. A094630, A094631.

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

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!.

cp's OEIS Frontend

A094631 Number of n-block 3-uniform T_0-covers.

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

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