A181571 Third column of triangle in A179898.

1, 6, 40, 300, 2475, 22022, 208208, 2068560, 21414900, 229523800, 2533942752, 28698821320, 332357673375, 3925129083750, 47167131780000, 575637606165600, 7123515376299300, 89266155250239000, 1131410294476020000, 14489559984061890000, 187330691180608155180, 2443121585638964379864

Offset

1,2

Links

Table of n, a(n) for n=1..22.

Crossrefs

Cf. A179898, A005700, A005701.

Sequence in context: A138240 A358598 A083805 * A231126 A341587 A006387

Adjacent sequences: A181568 A181569 A181570 * A181572 A181573 A181574

Keyword

nonn

Author

N. J. A. Sloane, Jan 30 2011

Status

approved