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A181571
Third column of triangle in A179898.
1
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
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jan 30 2011
STATUS
approved