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A054916 Number of connected unlabeled regular graphs with n nodes such that complement is also connected. 0
1, 0, 0, 0, 1, 2, 2, 12, 18, 158, 532, 18956, 389418, 50314722, 2942198334, 1698517035792, 442786966113484, 649978211591577760, 429712868499646362046, 2886054228478618206288948, 8835589045148342277740379344, 152929279364927228928017067050204, 1207932509391069805495173186013097090, 99162609848561525198669168626676490270856 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Table of n, a(n) for n=1..24.

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

FORMULA

a(n) = 2*A005177(n)-A005176(n) = A005177(n)-A068932(n).

CROSSREFS

Cf. A005176, A005177, A068932.

Sequence in context: A181813 A059187 A265458 * A194767 A302368 A202669

Adjacent sequences:  A054913 A054914 A054915 * A054917 A054918 A054919

KEYWORD

nonn,hard,changed

AUTHOR

N. J. A. Sloane, May 23 2000

EXTENSIONS

Terms a(11)-a(16) appended, journal link changed to article link, and second formula included, by Jason Kimberley, Oct 24 2009

a(17)-a(24) from Andrew Howroyd, May 19 2020

STATUS

approved

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Last modified May 29 03:06 EDT 2020. Contains 334696 sequences. (Running on oeis4.)