A049726 a(n) = Sum_{i=0..floor(n/2)} T(2i,n-2i), array T as in A049723.
1, 4, 18, 31, 73, 105, 204, 249, 412, 501, 760, 865, 1207, 1376, 1864, 2070, 2688, 2951, 3740, 4068, 5059, 5413, 6612, 7057, 8421, 8974, 10620, 11247, 13114, 13835, 16034, 16812, 19267, 20221, 22994, 23973, 27092, 28240
Offset: 0