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.

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A307935 Number of (undirected) Hamiltonian paths in the n-cocktail party graph.

Original entry on oeis.org

0, 4, 120, 6912, 631680, 84211200, 15432560640, 3722677862400, 1143584003358720, 435902085306777600, 201889940373209088000, 111673403387053395148800, 72713691524377589317632000, 55052849030095232395798118400, 47957058157063329359371173888000
Offset: 1

Views

Author

Eric W. Weisstein, May 06 2019

Keywords

Links

Crossrefs

Cf. A007060.

Formula

a(n) = A007060(n)/2.

A204841 (2n)! - 2^n*n!.

Original entry on oeis.org

0, 0, 16, 672, 39936, 3624960, 478955520, 87177646080, 20922779566080, 6402373519933440, 2432902004460748800, 1124000727695858073600, 620448401731277448806400, 403291461126554623829606400, 304888344611712432172380979200, 265252859812191015786434789376000
Offset: 0

Views

Author

Geoffrey Critzer, Jan 19 2012

Keywords

Comments

a(n) is the number of ways to seat (linearly order) n married couples so that at least one couple is separated.

Crossrefs

Cf. A007060.

Programs

  • Mathematica
    Table[(2n)! - 2^n n!, {n,0,20}]

Formula

a(n) = A010050(n) - A000165(n).
Previous Showing 11-12 of 12 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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