A059735 Number of complementary pairs of tournaments on n nodes.

1, 1, 2, 3, 10, 34, 272, 3528, 97144, 4870920, 452016608, 77054901728, 24271105072736, 14200712295904928, 15510501136026729216, 31765207922047709885696, 122456389219489134370435456, 891699423142395494501906828160, 12302820585630191716774996205431296

Offset: 1

Author

N. J. A. Sloane, Feb 09 2001

Keywords

• nonn
• easy

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..50
• Nevena Francetić, Sarada Herke, Ian M. Wanless, Parity of Sets of Mutually Orthogonal Latin Squares, arXiv:1703.04764 [math.CO], 2017. See Section 4.1.
• V. A. Liskovets, Some easily derivable sequences, J. Integer Sequences, 3 (2000), #00.2.2.

Crossrefs

Cf. A000568, A002785.

Programs

Mathematica

A000568 = Cases[Import["https://oeis.org/A000568/b000568.txt", "Table"], {, }][[All, 2]];
A002785 = Cases[Import["https://oeis.org/A002785/b002785.txt", "Table"], {, }][[All, 2]];
a[n_] := (A000568[[n + 1]] + A002785[[n]])/2;
Array[a, 19] (* Jean-François Alcover, Aug 27 2019 *)

Formula

Average of A000568 and A002785.

Extensions

More terms from Pab Ter (pabrlos2(AT)yahoo.com), Nov 06 2005

Terms a(18) and beyond from Andrew Howroyd, Sep 17 2018