OFFSET
0,2
COMMENTS
Also unsigned third column of triangle A136657 divided by 4.
REFERENCES
Ch. A. Charalambides, Enumerative Combinatorics, Chapman & Hall/CRC, Boca Raton, Florida, 2002, Table 8.3, p. 311, with s=-2, k=3 column/8.
FORMULA
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Feb 22 2008
STATUS
approved