A144272 Second column (m=2) of triangle S2hat(-1) = A144270.

1, 1, 4, 18, 129, 1095, 11880, 149940, 2218545, 37147005, 699281100, 14561835750, 332913128625, 8280095098275, 222659485448400, 6434896997529000, 198909798356894625, 6547761582390653625, 228681849947367316500, 8445341134525197152250, 328822530412023653630625

Offset: 0

Author

Wolfdieter Lang, Oct 09 2008

Keywords

• nonn
• easy

Crossrefs

Cf. A144270.

Cf. A001147 (column m=1), A144273 (column m=3).

Formula

a(n) = A144270(n+2,2), n>=0.