A107029 Diagonal sums of number triangle A107027.

1, 1, 3, 3, 5, 7, 11, 19, 35, 69, 151, 339, 829, 2111, 5607, 15737, 45289, 136477, 423279, 1353671, 4471673, 15114479, 52605755, 187162155, 681817179, 2539492249, 9646349779, 37415172217, 147745308403, 594368656811

Offset: 0

Author

Paul Barry, May 09 2005

Keywords

• easy
• nonn

Formula

a(n)=sum{k=0..floor(n/2), (n-2k-1)C((n-2k)*k, k)-(n-2k-2)*sum{j=0..k, C((n-2k)*k, j)}}