A098511 Diagonal sums of a matrix associated to the inverse of a Catalan scaled binomial matrix.

1, 1, 3, 6, 21, 54, 186, 479, 1938, 5795, 22888, 70781, 286443, 861463, 3592105, 11492256, 39274353, 148852401, 613876868, 1917516257, 8511689170, 25445125513, 100975365920, 390096404027, 1666653892303, 5319341488465

Offset: 0

Author

Paul Barry, Sep 11 2004

Keywords

• easy
• nonn

Comments

Diagonal sums of A098509.

Formula

a(n)=sum{k=0..floor(n/2), denominator((n-k+1)Binomial(n-k, k)/Binomial(2(n-k), n-k))}