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A055974 Number of unlabeled digraphs with loops (relations) on n nodes and with an odd number of arcs. 0
1, 4, 52, 1504, 145984, 48461696, 56141454464, 229148544420864, 3333310786076963968, 174695272746603272722432, 33301710992539090379269318144, 23278728241293494481773139193036800 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..12.

FORMULA

a(n)=(A000595(n)-A047832(n))/2.

CROSSREFS

Cf. A054960.

Sequence in context: A287699 A280571 A277353 * A009671 A015001 A317829

Adjacent sequences:  A055971 A055972 A055973 * A055975 A055976 A055977

KEYWORD

easy,nonn

AUTHOR

Vladeta Jovovic, Jul 19 2000

STATUS

approved

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Last modified March 23 11:07 EDT 2019. Contains 321424 sequences. (Running on oeis4.)