OFFSET
1,2
LINKS
Vladimir Kruchinin and D. V. Kruchinin, Composita and their properties, arXiv:1103.2582 [math.CO], 2011-2013.
FORMULA
T(n,k):=k/(3*n-2*k)*sum(i=0..n-k, binomial(3*n-2*k,n-k-i)*binomial(3*n-2*k+i-1,3*n-2*k-1)), n>=k>0.
PROG
(Maxima)
T(n, k):=k/(3*n-2*k)*sum(binomial(3*n-2*k, n-k-i)*binomial(3*n-2*k+i-1, 3*n-2*k-1), i, 0, n-k);
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Vladimir Kruchinin, Mar 16 2011
STATUS
approved