A062716 Number of arrangements of 1,2,..,n*n in an n X n matrix such that each row is increasing or decreasing.

1, 2, 24, 13440, 1009008000, 19947543780003840, 170891375144777551827763200, 942542805268120269309770939139883008000, 4650425326497486529782791149613966242353671284224000000

Offset: 1

Author

Ahmed Fares (ahmedfares(AT)my-deja.com), Jul 14 2001

Keywords

• nonn

Crossrefs

Cf. A034841.

Formula

a(1) = 1 and for n >= 2: a(n) = 2^n * A034841(n) = 2^n * (n^2)! / (n!)^n.

Extensions

More terms from Vladeta Jovovic, Jul 18 2001