The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 17 |
| 4 | 95 |
| 5 | 649 |
| 6 | 5423 |
| 7 | 53345 |
| 8 | 604570 |
| 9 | 7744990 |
| 10 | 110596370 |
| 11 | 1740967790 |
| 12 | 29943077149 |
| 13 | 558541778035 |
| 14 | 11229820022013 |
| 15 | 242071441524480 |
| 16 | 5568954194762675 |
| 17 | 136181762611151941 |
| 18 | 3527284819779421843 |
| 19 | 96465042641948254298 |
| 20 | 2777679881076121497601 |
[1,1,4,17,95,649,5423,53345,604570,7744990, 110596370,1740967790,29943077149,558541778035, 11229820022013,242071441524480,5568954194762675, 136181762611151941,3527284819779421843, 96465042641948254298,2777679881076121497601] |