A144883 Second column (m=2) of triangle A144881 (S1hat(3)).

1, 3, 21, 96, 684, 4320, 35640, 293760, 2881440, 29695680, 345643200, 4296499200, 58518028800, 851751936000, 13338801100800, 222145265664000, 3934764739584000, 73675580977152000, 1455693852146688000, 30238671742304256000, 659012259039805440000

Offset: 0

Author

Wolfdieter Lang, Oct 09 2008

Keywords

• nonn
• easy

Crossrefs

Cf. A144881, A001710 (first column), A144884 (third column).

Formula

a(n) = A144881(n+2,2), n>=0.