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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 33 |
| 5 | 156 |
| 6 | 1070 |
| 7 | 7515 |
| 8 | 59151 |
| 9 | 483925 |
| 10 | 4136964 |
| 11 | 36416865 |
| 12 | 329048627 |
| 13 | 3037029030 |
| 14 | 28553451498 |
| 15 | 272766018806 |
| 16 | 2642420298576 |
| 17 | 25916954091582 |
| 18 | 257009789443925 |
| 19 | 2573962338306141 |
| 20 | 26008719387850068 |
| 21 | 264933535266372732 |
[1,3,7,33,156,1070,7515,59151,483925,4136964, 36416865,329048627,3037029030,28553451498, 272766018806,2642420298576,25916954091582, 257009789443925,2573962338306141, 26008719387850068,264933535266372732] |