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A054949 Number of labeled semi-strong digraphs on n nodes with an odd number of components. 1
1, 1, 19, 1612, 565276, 734799976, 3523103676184, 63519230066936512, 4400411105398828102336, 1190433708177460323642937216, 1270463865199882936737403300783744, 5381067966904826663696685903449569172992, 90765788839502187660342772995967835888789034496 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..13.

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

FORMULA

a(n) = (A054948(n) + A054947(n))/2. - Andrew Howroyd, Sep 10 2018

CROSSREFS

Cf. A054947, A054948, A054950.

Sequence in context: A217830 A002115 A223498 * A242564 A068748 A289736

Adjacent sequences:  A054946 A054947 A054948 * A054950 A054951 A054952

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, May 24 2000

EXTENSIONS

More terms from Vladeta Jovovic, Mar 11 2003

STATUS

approved

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Last modified November 15 11:35 EST 2018. Contains 317238 sequences. (Running on oeis4.)