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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 14 |
| 4 | 76 |
| 5 | 450 |
| 6 | 2818 |
| 7 | 18352 |
| 8 | 123028 |
| 9 | 843345 |
| 10 | 5884227 |
| 11 | 41650479 |
| 12 | 298352365 |
| 13 | 2158751879 |
| 14 | 15754446893 |
| 15 | 115830820439 |
| 16 | 857147952469 |
| 17 | 6379136387303 |
| 18 | 47715901304501 |
| 19 | 358529599468636 |
| 20 | 2704884469806606 |
| 21 | 20481615947325089 |
| 22 | 155605509972859999 |
| 23 | 1185779099027494848 |
[1,1,3,14,76,450,2818,18352,123028,843345,5884227, 41650479,298352365,2158751879,15754446893, 115830820439,857147952469,6379136387303, 47715901304501,358529599468636,2704884469806606, 20481615947325089,155605509972859999, 1185779099027494848] |