The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| -2 | 0 |
| -1 | 1 |
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 9 |
| 5 | 56 |
| 6 | 65 |
| 7 | 186 |
| 8 | 437 |
| 9 | 1060 |
| 10 | 1497 |
| 11 | 2557 |
| 12 | 16839 |
| 13 | 19396 |
| 14 | 3488723 |
| 15 | 160500654 |
| 16 | 163989377 |
| 17 | 324490031 |
| 18 | 1137459470 |
| 19 | 2599408971 |
| 20 | 3736868441 |
| 21 | 6336277412 |
| 22 | 22745700677 |
| 23 | 142810481474 |
| 24 | 451177145099 |
| 25 | 593987626573 |
[0,1,0,1,1,2,9,56,65,186,437,1060,1497,2557,16839, 19396,3488723,160500654,163989377,324490031, 1137459470,2599408971,3736868441,6336277412, 22745700677,142810481474,451177145099, 593987626573] |