A222202 - OEIS

%I #20 Jan 01 2019 06:31:06

%S 1,18,13903,360783593,303872744726644,8217125138015950451626,

%T 7095967027221343377167292602835,

%U 195081705501438193439250404333039349462635,170400931523966165754313513175663906434875251822099185,4722705723996809689481769489662532396060449405036901391459114641198

%N Number of ways to cover the 2n X 2n grid graph by vertex disjoint cycles.

%H Andrew Howroyd, <a href="/A222202/b222202.txt">Table of n, a(n) for n = 1..12</a>

%H Peter Tittmann, <a href="http://web.archive.org/web/20070715034048/http://www.htwm.de/~peter/research/enumeration.html">Enumeration in graphs: counting Hamiltonian cycles</a> [Archived link]

%Y Cf. A222203, A222204.

%K nonn

%O 1,2

%A _N. J. A. Sloane_, Feb 14 2013

%E a(10)-a(12) from _Andrew Howroyd_, Nov 16 2015