A220866 Number of perfect matchings in the graph Q_3 X C_n.

9, 272, 13680, 589185, 8569929, 275875712, 5108424393, 145226575873, 3035328931440, 80547660499745, 1803169706739465, 46038870317103360, 1071178606116233481, 26773612043494621985, 636336484914189068400, 15721552047510746176513, 378017352673144521373641, 9281019645236843136077696, 224562195991613981197986633, 5494808685530499611855429505

Offset

1,1

Links

Andrew Howroyd, Table of n, a(n) for n = 1..30

S. Butler and S. Osborne, Counting tilings by taking walks, 2012.

Crossrefs

Sequence in context: A336195 A028456 A180358 * A197597 A197981 A188812

Adjacent sequences: A220863 A220864 A220865 * A220867 A220868 A220869

Keyword

nonn

Author

N. J. A. Sloane, Dec 27 2012

Extensions

a(1)-a(2), a(9)-a(20) from Andrew Howroyd, Nov 15 2015

Status

approved