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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 36 |
| 5 | 241 |
| 6 | 2038 |
| 7 | 21113 |
| 8 | 259416 |
| 9 | 3711889 |
| 10 | 60941194 |
| 11 | 1132624593 |
| 12 | 23584844132 |
| 13 | 545415797577 |
| 14 | 13900638671182 |
| 15 | 387909856253257 |
| 16 | 11785121609470896 |
| 17 | 387841948278314657 |
| 18 | 13764450667964758290 |
| 19 | 524703399684950744353 |
| 20 | 21407375104944503282620 |
[1,1,2,7,36,241,2038,21113,259416,3711889, 60941194,1132624593,23584844132,545415797577, 13900638671182,387909856253257,11785121609470896, 387841948278314657,13764450667964758290, 524703399684950744353,21407375104944503282620] |