The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 15 |
| 3 | 112 |
| 4 | 309 |
| 5 | 2449 |
| 6 | 7004 |
| 7 | 56977 |
| 8 | 166128 |
| 9 | 1371673 |
| 10 | 4046880 |
| 11 | 33736358 |
| 12 | 100328902 |
| 13 | 842011587 |
| 14 | 2518460195 |
| 15 | 21241145637 |
| 16 | 63807550099 |
| 17 | 540215987658 |
| 18 | 1628274148825 |
| 19 | 13827134974963 |
| 20 | 41789656029594 |
| 21 | 355743023641567 |
| 22 | 1077551461258952 |
| 23 | 9191485155260759 |
[1,6,15,112,309,2449,7004,56977,166128,1371673, 4046880,33736358,100328902,842011587,2518460195, 21241145637,63807550099,540215987658, 1628274148825,13827134974963,41789656029594, 355743023641567,1077551461258952,9191485155260759] |