A152799 Column 2 of triangle A152798; first differences of A122889.
1, 1, 3, 6, 15, 40, 113, 348, 1148, 4045, 15203, 60710, 256688, 1145887, 5386283, 26590338, 137537012, 743766652, 4196681423, 24661702224, 150676068558, 955611495432, 6281965526173, 42745748797360, 300690981532778
Offset: 0