A136660 Unsigned fourth column (k=3) of triangle A136656 divided by 8.

1, 18, 255, 3465, 47880, 687960, 10372320, 164656800, 2754259200, 48518870400, 899026128000, 17495593315200, 356995102464000, 7625049239808000, 170196434343936000, 3963602854987776000, 96160451873181696000

Offset: 0

Author

Wolfdieter Lang, Feb 22 2008

Keywords

• nonn
• easy

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.

Crossrefs

Cf. A136656, A136659 (column k=2), A136661 (column k=4).

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).