1,2
Number of open directed king's tours on the nxn board.
Eric Weisstein's World of Mathematics, King's Tour Graph
Cf. A140521, A096969, A137891.
Sequence in context: A062313 A062528 A175604 * A204559 A078522 A195130
Adjacent sequences: A158648 A158649 A158650 * A158652 A158653 A158654
nonn,more
E. W. Weisstein (eric(AT)weisstein.com), Mar 23, 2009
a(5) from Max Alekseyev (maxale(AT)gmail.com), May 03 2009