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A136660
Unsigned fourth column (k=3) of triangle A136656 divided by 8.
3
1, 18, 255, 3465, 47880, 687960, 10372320, 164656800, 2754259200, 48518870400, 899026128000, 17495593315200, 356995102464000, 7625049239808000, 170196434343936000, 3963602854987776000, 96160451873181696000
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
a(n) = |A136656(n+3,3)|/8, n>=0.
E.g.f.: (2+18*x+3*x^2-12*x^3+3*x^4)/(2*(1-x)^9) (derived from the one given for the column k=3 under A136656).
CROSSREFS
Cf. A136656, A136659 (column k=2), A136661 (column k=4).
Sequence in context: A062141 A157708 A159537 * A374880 A374862 A362808
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Feb 22 2008
STATUS
approved