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

0,2

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.

Links

Table of n, a(n) for n=0..16.

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 * A362808 A365137 A255372

Adjacent sequences: A136657 A136658 A136659 * A136661 A136662 A136663

Keyword

nonn,easy

Author

Wolfdieter Lang, Feb 22 2008

Status

approved