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A238819 Number of Hamiltonian cycles on 4n+2 X 4n+2 grid with at least 90 degree rotational symmetry. 1
1, 2, 204, 510718, 31008619522, 43911490791183200, 1424639466911800364132674, 1048492580133908850434091619741314 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..7.

Ed Wynn, Enumeration of nonisomorphic Hamiltonian cycles on square grid graphs, arXiv preprint arXiv:1402.0545 [math.CO], 2014.

CROSSREFS

Cf. A003763.

Sequence in context: A203773 A209185 A216608 * A110899 A281126 A220940

Adjacent sequences:  A238816 A238817 A238818 * A238820 A238821 A238822

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mar 05 2014

EXTENSIONS

a(5)-a(7) from Andrew Howroyd, Apr 06 2016

STATUS

approved

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Last modified December 7 09:33 EST 2019. Contains 329843 sequences. (Running on oeis4.)