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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 5 |
| 5 | 16 |
| 6 | 79 |
| 7 | 421 |
| 8 | 2673 |
| 9 | 19216 |
| 10 | 156021 |
| 11 | 1411873 |
| 12 | 14117773 |
| 13 | 154730720 |
| 14 | 1845959179 |
| 15 | 23826445501 |
| 16 | 330951133537 |
| 17 | 4923574598112 |
| 18 | 78123812086441 |
| 19 | 1317174439409409 |
| 20 | 23517962293307701 |
| 21 | 443340968936640496 |
| 22 | 8799729204814165223 |
| 23 | 183448995762912568885 |
[1,0,1,1,5,16,79,421,2673,19216,156021,1411873, 14117773,154730720,1845959179,23826445501, 330951133537,4923574598112,78123812086441, 1317174439409409,23517962293307701, 443340968936640496,8799729204814165223, 183448995762912568885] |