OFFSET
0,2
COMMENTS
Also the number of ascending runs of length n+8 in the permutations of [2n+8].
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..300
FORMULA
MAPLE
a:= proc(n) option remember; `if`(n<2, 1+17*n, 2*(n+4)*(2*n+7)*
(n^3+18*n^2+90*n+89)*a(n-1)/((n+10)*(n^3+15*n^2+57*n+16)))
end:
seq(a(n), n=0..25);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Oct 16 2013
STATUS
approved