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A135388 Number of (directed) Eulerian circuits on the complete graph K_{2n+1}. 1
2, 264, 129976320, 911520057021235200, 257326999238092967427785160130560, 6705710151431658873046319662156165939200000000000000, 32132958735643556926111996291480203406145819659840760945049600000000000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

B. D. McKay, Applications of a technique for labeled enumeration, Congress. Numerantium, 40 (1983), 207-221.

LINKS

Table of n, a(n) for n=1..7.

Brendan D. McKay and Robert W. Robinson, Asymptotic enumeration of Eulerian circuits in the complete graph, Combinatorics, Probability and Computing, 7 (1998), 437-449.

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

Cf. A007082.

Sequence in context: A137105 A216984 A007082 * A238983 A188964 A278771

Adjacent sequences:  A135385 A135386 A135387 * A135389 A135390 A135391

KEYWORD

nonn

AUTHOR

Max Alekseyev, Dec 10 2007

STATUS

approved

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Last modified October 18 12:18 EDT 2019. Contains 328160 sequences. (Running on oeis4.)