OFFSET
0,2
COMMENTS
Also the number of binary words with 10n 1's and 10 0's such that for every prefix the number of 1's is >= the number of 0's.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
Wikipedia, Young tableau
FORMULA
G.f.: (9*x^10 -99*x^9 -140503*x^8 -25387417*x^7 -510202946*x^6 -2566871318*x^5 -4166581331*x^4 -2313217577*x^3 -402028913*x^2 -15553109*x -16796)*x / (x-1)^11.
a(n) = C(10*n+10,10)*(10*n-9)/(10*n+1) for n>0, a(0) = 0.
MAPLE
a:= n-> max(0, binomial(10*n+10, 10)*(10*n-9)/(10*n+1)):
seq(a(n), n=0..30);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Aug 16 2012
STATUS
approved