| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 50 |
| 4 | 490 |
| 5 | 2618 |
| 6 | 9519 |
| 7 | 28432 |
| 8 | 70796 |
| 9 | 157912 |
| 10 | 321161 |
| 11 | 610482 |
| 12 | 1082570 |
| 13 | 1848362 |
| 14 | 3003015 |
| 15 | 4716792 |
| 16 | 7204604 |
| 17 | 10730528 |
| 18 | 15530189 |
| 19 | 22093410 |
| 20 | 30723078 |
| 21 | 42146178 |
| 22 | 56981411 |
| 23 | 75952240 |
| 24 | 99685104 |
| 25 | 129757248 |
[0,1,50,490,2618,9519,28432,70796,157912,321161, 610482,1082570,1848362,3003015,4716792,7204604, 10730528,15530189,22093410,30723078,42146178, 56981411,75952240,99685104,129757248] |