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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 8 |
| 4 | 31 |
| 5 | 83 |
| 6 | 309 |
| 7 | 977 |
| 8 | 3571 |
| 9 | 12395 |
| 10 | 45458 |
| 11 | 165876 |
| 12 | 617495 |
| 13 | 2316191 |
| 14 | 8773838 |
| 15 | 33493548 |
| 16 | 128840353 |
| 17 | 498456315 |
| 18 | 1941252054 |
| 19 | 7594394344 |
| 20 | 29871433149 |
| 21 | 117966578225 |
| 22 | 467857554197 |
| 23 | 1862361268887 |
| 24 | 7438937047067 |
| 25 | 29811320860773 |
| 26 | 119819502795074 |
| 27 | 482960010597006 |
| 28 | 1951744104721491 |
[1,1,4,8,31,83,309,977,3571,12395,45458,165876, 617495,2316191,8773838,33493548,128840353, 498456315,1941252054,7594394344,29871433149, 117966578225,467857554197,1862361268887, 7438937047067,29811320860773,119819502795074, 482960010597006,1951744104721491] |