A099236 Sums of antidiagonals of A099233.

1, 2, 3, 5, 9, 18, 39, 91, 226, 594, 1643, 4763, 14419, 45444, 148714, 504150, 1766930, 6390720, 23815168, 91306968, 359694457, 1454213026, 6027213531, 25583995337, 111118605583, 493407322280, 2238131105770, 10363617299670, 48954143141361

Offset: 0

Author

Paul Barry, Oct 08 2004

Keywords

• easy
• nonn

Formula

a(n)=sum{j=0..n, sum{k=0..n-j, binomial(j(n-j-k), k)}}