OFFSET
0,3
EXAMPLE
Table begins:
1;
1;
2, 1;
5, 6;
14, 30, 6;
42, 140, 75;
132, 630, 630, 75;
429, 2772, 4410, 1470;
1430, 12012, 27720, 17640, 1470;
4862, 51480, 162162, 166320, 39690;
16796, 218790, 900900, 1351350, 623700, 39690; ...
PROG
(PARI) T(n, k)=binomial(2*n-2*k, n-k)/(n-k+1)*binomial(2*k, k)*k!/2^k*binomial(n, 2*k)
(PARI) T(n, k)=(2*n-2*k)!*n!/k!/(n-k)!/(n-k+1)!/(n-2*k)!/2^k
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Paul D. Hanna, Nov 19 2006
STATUS
approved