cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A357242 Number of n node tournaments that have exactly two circular triads.

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%I A357242 #21 Jan 06 2025 06:31:22
%S A357242 24,240,2240,21840,228480,2580480,31449600,412473600,5801241600,
%T A357242 87178291200,1394852659200,23683435776000,425430061056000,
%U A357242 8062248370176000,160770717499392000,3365514444644352000,73798027581358080000,1691677863018823680000,40464026199993876480000
%N A357242 Number of n node tournaments that have exactly two circular triads.
%H A357242 Ian R. Harris and Ryan P. A. McShane, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL27/McShane/mcshane1.html">Counting Tournaments with a Specified Number of Circular Triads</a>, Journal of Integer Sequences, Vol. 27 (2024), Article 24.8.7. See pages 2, 23.
%H A357242 J. B. Kadane, <a href="https://doi.org/10.1214/aoms/1177699532">Some equivalence classes in paired comparisons</a>, The Annals of Mathematical Statistics, 37 (1966), 488-494.
%F A357242 a(n) = n!*(n - 3 + (1/18)*(n - 4)*(n - 5)) (proven by Kadane).
%e A357242 For n = 4 the a(4) = 24 solution is 4!*(4 - 3 + (1/18)*(4 - 4)*(4 - 5)) = 24.
%o A357242 (R) fact(n)*(n-3+(1/18)*(n-4)*(n-5))
%K A357242 nonn,easy
%O A357242 4,1
%A A357242 _Ian R Harris_, Sep 19 2022