A124997 Number of fault-free domino tilings (or dimer coverings) of a 2n X 2n square.

0, 0, 0, 25506, 1759280998, 854818404562894, 3588226034666378581610, 138311081613064367684548901556, 50272239752141442901464758051467073726, 174927321882862834702052846250836696969014873138, 5889117928937174007411459040006660524033737246962655301188

Offset

1,4

Comments

Enumerates a subclass of the things counted by A004003.

"Fault-free" means that every straight line through the interior of the square hits the interior of some domino.

Links

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

Crossrefs

Cf. A004003.

Sequence in context: A339673 A324635 A242141 * A031837 A237865 A202646

Adjacent sequences: A124994 A124995 A124996 * A124998 A124999 A125000

Keyword

nonn

Author

Don Knuth, Jun 26 2008

Extensions

a(7) from Alois P. Heinz, Oct 19 2015

a(8)-a(11) from Xu Mingkuan, Dec 23 2016

Status

approved