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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 28 |
| 4 | 171 |
| 5 | 1113 |
| 6 | 7590 |
| 7 | 53588 |
| 8 | 388519 |
| 9 | 2876003 |
| 10 | 21648065 |
| 11 | 165193576 |
| 12 | 1275043280 |
| 13 | 9936953788 |
| 14 | 78087083456 |
| 15 | 618049278976 |
| 16 | 4922606097263 |
| 17 | 39425205882007 |
| 18 | 317316076325015 |
| 19 | 2565216211152700 |
| 20 | 20819872339143179 |
| 21 | 169586043613302169 |
| 22 | 1385856599443533442 |
[1,1,5,28,171,1113,7590,53588,388519,2876003, 21648065,165193576,1275043280,9936953788, 78087083456,618049278976,4922606097263, 39425205882007,317316076325015,2565216211152700, 20819872339143179,169586043613302169, 1385856599443533442] |