OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
FORMULA
G.f.: -x*(1+1709*x+42582*x^2+146714*x^3+104077*x^4+13665*x^5+132*x^6) / (x-1)^7.
a(0) = 0, a(n) = 1+(12+(65+(208+(429+(572+429*(n-1)) * (n-1)) * (n-1)) * (n-1)) * (n-1)) * (n-1) for n>0.
EXAMPLE
a(1) = 1: a^14 (with 1-ary alphabet {a}).
MAPLE
a:= n-> `if`(n=0, 0, (x-> 1+(12+(65+(208+(429+(572+429*x)*x)*x)
*x)*x)*x)(n-1)):
seq(a(n), n=0..30);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 02 2011
STATUS
approved