

A143402


Expansion of x^k/Prod_{t=k..2k}(1tx) for k=7.


2



0, 0, 0, 0, 0, 0, 0, 1, 84, 3990, 141120, 4138827, 106469748, 2484848080, 53791898160, 1096912870053, 21307466872692, 397605494092170, 7173885616672320, 125794299357058879, 2152559266567924116, 36065247772657686660, 593280221500152370800
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,9


COMMENTS

a(n) is also the number of forests of 7 labeled rooted trees of height at most 1, with n labels, where any root may contain >= 1 labels.


LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..300
Index entries for sequences related to rooted trees


FORMULA

G.f.: x^7/((17x)(18x)(19x)(110x)(111x)(112x)(113x)(114x)).


MAPLE

a := proc(k::nonnegint) local M; M := Matrix(k+1, (i, j)> if (i=j1) then 1 elif j=1 then [seq(1* coeff (product (1t*x, t=k..2*k), x, u), u=1..k+1)][i] else 0 fi); p> (M^p)[1, k+1] end(7): seq (a(n), n=0..30);


CROSSREFS

7th column of A143395.
Sequence in context: A035806 A017747 A223959 * A004379 A075906 A075909
Adjacent sequences: A143399 A143400 A143401 * A143403 A143404 A143405


KEYWORD

nonn


AUTHOR

Alois P. Heinz, Aug 12 2008


STATUS

approved



