OFFSET
0,2
COMMENTS
Triangle T(n,k) for A(x)^k = Sum_{n>=k} T(n,k)*x^n, where o.g.f. A(x) satisfies A(x) = (1+x*A(x)^2)/(1-x*A(x)^2). - Vladimir Kruchinin, Mar 16 2011
LINKS
G. C. Greubel, Table of n, a(n) for the first 100 rows, flattened
Vladimir Kruchinin, D. V. Kruchinin, Composita and their properties, arXiv:1103.2582 [math.CO], 2011-2013.
FORMULA
T(0, 0) = 1; T(n, k) = 0 if k<0 or if k>n; T(n, k) = Sum_{j, j>=0} T(n-1, k-1+j)*A006318(j).
Sum_{k, k>=0} T(n, k) = A108442(n+1).
T(n,k) = k/(2*n-k)*Sum_{i=0,n-k} binomial(2*n-k,n-k-i)*binomial(2*n-k+i-1,2*n-k-1), n >= k > 0. - Vladimir Kruchinin, Mar 16 2011
MATHEMATICA
T[n_, k_] := (k/(2*n - k))*Sum[Binomial[2*n - k, n - k - j]*Binomial[2*n - k + j - 1, 2*n - k - 1], {j, 0, n - k}]; Table[T[n, k], {n, 0, 25}, {k, 1, n}] // Flatten (* G. C. Greubel, Sep 05 2017 *)
PROG
(PARI) for(n=0, 25, for(k=1, n, print1((k/(2*n-k))*sum(i=0, n-k, binomial(2*n-k, n-k-i)*binomial(2*n-k+i-1, 2*n-k-1)), ", "))) \\ G. C. Greubel, Sep 05 2017
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Philippe Deléham, Sep 15 2005
STATUS
approved