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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 18 |
| 3 | 95 |
| 4 | 693 |
| 5 | 4893 |
| 6 | 40506 |
| 7 | 338277 |
| 8 | 3110310 |
| 9 | 29270549 |
| 10 | 294099936 |
| 11 | 3036380607 |
| 12 | 32913111931 |
| 13 | 366636699553 |
| 14 | 4245071555734 |
| 15 | 50447432122893 |
| 16 | 619067368928568 |
| 17 | 7783987091482635 |
| 18 | 100610823839282548 |
| 19 | 1330119345038208405 |
[1,3,18,95,693,4893,40506,338277,3110310,29270549, 294099936,3036380607,32913111931,366636699553, 4245071555734,50447432122893,619067368928568, 7783987091482635,100610823839282548, 1330119345038208405] |