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A054959 Number of labeled connected Eulerian digraphs with n nodes and an odd number of edges. 2
0, 0, 2, 56, 3488, 664688, 434127152, 1019647579136, 8819902136934912, 284798318582888580608, 34636901578294133260750592, 15970288165992077917878979939328, 28060652850285225214988677641875677184, 188680826646319054103468721801532834939660288 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..14.

V. A. Liskovets, Some easily derivable sequences, J. Integer Sequences, 3 (2000), #00.2.2.

FORMULA

a(n) = (A054957(n) - (n-1)!)/2. - Andrew Howroyd, Sep 10 2018

MATHEMATICA

A054957 = Cases[Import["https://oeis.org/A054957/b054957.txt", "Table"], {_, _}][[All, 2]];

a[n_] := (A054957[[n]] - (n - 1)!)/2;

Array[a, 14] (* Jean-Fran├žois Alcover, Sep 13 2019 *)

CROSSREFS

Cf. A058338, A054955, A007080, A054956, A058337, A054958, A054957.

Sequence in context: A193475 A246001 A009555 * A206305 A325291 A326551

Adjacent sequences:  A054956 A054957 A054958 * A054960 A054961 A054962

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, May 24 2000

EXTENSIONS

More terms from Vladeta Jovovic, Mar 06 2001

a(12)-a(14) from Andrew Howroyd, Sep 10 2018

STATUS

approved

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Last modified February 22 04:58 EST 2020. Contains 332115 sequences. (Running on oeis4.)