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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 15 |
| 5 | 106 |
| 6 | 982 |
| 7 | 11383 |
| 8 | 159595 |
| 9 | 2636590 |
| 10 | 50278058 |
| 11 | 1088631886 |
| 12 | 26409797526 |
| 13 | 710034913212 |
| 14 | 20963748887980 |
| 15 | 674521750652735 |
| 16 | 23497037813799795 |
| 17 | 881180319357526102 |
| 18 | 35400836754598975554 |
| 19 | 1516991897621421273210 |
[1,1,3,15,106,982,11383,159595,2636590,50278058, 1088631886,26409797526,710034913212, 20963748887980,674521750652735,23497037813799795, 881180319357526102,35400836754598975554, 1516991897621421273210] |