| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 15 |
| 5 | 43 |
| 6 | 143 |
| 7 | 437 |
| 8 | 1417 |
| 9 | 4989 |
| 10 | 16662 |
| 11 | 57588 |
| 12 | 210213 |
| 13 | 738585 |
| 14 | 2655474 |
| 15 | 9938226 |
| 16 | 36093321 |
| 17 | 133318933 |
| 18 | 508179320 |
| 19 | 1889378414 |
| 20 | 7117855813 |
| 21 | 27515624661 |
| 22 | 104113056537 |
| 23 | 398189050433 |
| 24 | 1556540328859 |
| 25 | 5970705339763 |
| 26 | 23109973111658 |
| 27 | 91161048731052 |
| 28 | 353543822644935 |
| 29 | 1381772586075051 |
| 30 | 5491843697255583 |
[1,1,2,6,15,43,143,437,1417,4989,16662,57588, 210213,738585,2655474,9938226,36093321,133318933, 508179320,1889378414,7117855813,27515624661, 104113056537,398189050433,1556540328859, 5970705339763,23109973111658,91161048731052, 353543822644935,1381772586075051,5491843697255583] |