OFFSET
1,1
REFERENCES
B. D. McKay, Applications of a technique for labeled enumeration, Congress. Numerantium, 40 (1983), 207-221.
LINKS
Max Alekseyev, Table of n, a(n) for n = 1..10
Brendan D. McKay and Robert W. Robinson, Asymptotic enumeration of Eulerian circuits in the complete graph, Combinatorics, Probability and Computing, 7 (1998), 437-449.
G. Tarry, Géométrie de situation: Nombre de manières distinctes de parcourir en une seule course toutes les allées d'un labyrinthe rentrant, en ne passant qu'une seule fois par chacune des allées, Comptes Rendus Assoc. Franç. Avance. Sci. 15, part 2 (1886), pp. 49-53.
Eric Weisstein's World of Mathematics, Complete Graph
Eric Weisstein's World of Mathematics, Eulerian Cycle
FORMULA
a(n) = A007082(n) * (n-1)!^(2*n+1).
MATHEMATICA
Table[2 Length[FindEulerianCycle[CompleteGraph[2 n + 1], All]], {n, 3}] (* Eric W. Weisstein, Jan 09 2018 *)
(* a(3) requires a very large amount of memory *)
CROSSREFS
KEYWORD
nonn,walk
AUTHOR
Max Alekseyev, Dec 10 2007
STATUS
approved