| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 5 |
| 5 | 16 |
| 6 | 79 |
| 7 | 421 |
| 8 | 2674 |
| 9 | 19244 |
| 10 | 156612 |
| 11 | 1423028 |
| 12 | 14320350 |
| 13 | 158390872 |
| 14 | 1912977222 |
| 15 | 25083283995 |
| 16 | 355246037162 |
| 17 | 5409471180024 |
| 18 | 88200546561838 |
| 19 | 1534120589972637 |
| 20 | 28369229081383675 |
| 21 | 556021169447494656 |
| 22 | 11517512836906556032 |
| 23 | 251487262264563372960 |
[1,0,1,1,5,16,79,421,2674,19244,156612,1423028, 14320350,158390872,1912977222,25083283995, 355246037162,5409471180024,88200546561838, 1534120589972637,28369229081383675, 556021169447494656,11517512836906556032, 251487262264563372960] |