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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 14 |
| 4 | 77 |
| 5 | 464 |
| 6 | 2968 |
| 7 | 19806 |
| 8 | 136407 |
| 9 | 962618 |
| 10 | 6925550 |
| 11 | 50611024 |
| 12 | 374661606 |
| 13 | 2803693956 |
| 14 | 21174556020 |
| 15 | 161187646856 |
| 16 | 1235473430325 |
| 17 | 9526917196888 |
| 18 | 73855947802228 |
| 19 | 575279950326078 |
| 20 | 4500074754843640 |
| 21 | 35336594070610722 |
| 22 | 278443821633875298 |
| 23 | 2201014965056842878 |
[0,1,3,14,77,464,2968,19806,136407,962618,6925550, 50611024,374661606,2803693956,21174556020, 161187646856,1235473430325,9526917196888, 73855947802228,575279950326078,4500074754843640, 35336594070610722,278443821633875298, 2201014965056842878] |