The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 22 |
| 4 | 108 |
| 5 | 616 |
| 6 | 4034 |
| 7 | 29920 |
| 8 | 249925 |
| 9 | 2316316 |
| 10 | 23674817 |
| 11 | 264329176 |
| 12 | 3207278249 |
| 13 | 42011308543 |
| 14 | 591460307156 |
| 15 | 8905905152797 |
| 16 | 142897741683228 |
| 17 | 2433947385964345 |
| 18 | 43873382718719948 |
| 19 | 834402502632546553 |
| 20 | 16699964488044322204 |
| 21 | 350869837371828862606 |
[1,5,22,108,616,4034,29920,249925,2316316, 23674817,264329176,3207278249,42011308543, 591460307156,8905905152797,142897741683228, 2433947385964345,43873382718719948, 834402502632546553,16699964488044322204, 350869837371828862606] |