login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A059375
Number of seating arrangements for the ménage problem.
8
1, 0, 0, 12, 96, 3120, 115200, 5836320, 382072320, 31488549120, 3191834419200, 390445460697600, 56729732529254400, 9659308746908620800, 1905270127543015833600, 431026303509734220288000, 110865322076320374571008000, 32172949121885378686623744000
OFFSET
0,4
COMMENTS
The "probleme des menages" asks for the number of gender-alternating seating arrangements for n couples around a circular table with the condition that no two spouses are seated adjacently. - Paul C. Kainen and Michael Somos, Mar 11 2011
REFERENCES
L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 184, mu*(n).
H. J. Ryser, Combinatorial Mathematics. Mathematical Association of America, Carus Mathematical Monograph 14, 1963, p. 32. equation (2.3).
LINKS
M. A. Alekseyev, Weighted de Bruijn Graphs for the Menage Problem and Its Generalizations. Lecture Notes in Computer Science 9843 (2016), 151-162. doi:10.1007/978-3-319-44543-4_12 arXiv:1510.07926
V. Baltic, On the number of certain types of strongly restricted permutations, Appl. An. Disc. Math. 4 (2010), 119-135. doi:10.2298/AADM1000008B
K. P. Bogart and P. G. Doyle, Nonsexist solution of the menage problem, Amer. Math. Monthly 93:7 (1986), 514-519.
Vladimir Shevelev, Peter J. C. Moses, The ménage problem with a known mathematician, arXiv:1101.5321 [math.CO], 2011, 2015.
Wikipedia, Menage Problem
FORMULA
a(n) = A000179(n) * 2 * n!.
a(n) = A094047(n) * 2 * n.
EXAMPLE
a(3) = 12 because there is a unique seating arrangement up to circular and clockwise / counterclockwise symmetry. - Paul C. Kainen and Michael Somos, Mar 11 2011
MATHEMATICA
a[0] = 1; a[1] = 0; a[n_] := 4n n! Sum[(-1)^k Binomial[2n-k, k] (n-k)! / (2n-k), {k, 0, n}]; Table[a[n], {n, 0, 17}] (* Jean-François Alcover, Jun 19 2017, from 1st formula *)
PROG
(PARI) {a(n) = local(A); if( n<3, n==0, A = vector(n); A[3] = 1; for(k=4, n, A[k] = (k * (k - 2) * A[k-1] + k * A[k-2] - 4 * (-1)^k) / (k-2)); 2 * n! * A[n])} /* Michael Somos, Mar 11 2011 */
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jan 28 2001
STATUS
approved