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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 12 |
| 3 | 51 |
| 4 | 182 |
| 5 | 753 |
| 6 | 3061 |
| 7 | 12503 |
| 8 | 51668 |
| 9 | 213279 |
| 10 | 880209 |
| 11 | 3634766 |
| 12 | 15007471 |
| 13 | 61961064 |
| 14 | 255823889 |
| 15 | 1056237984 |
| 16 | 4360961496 |
| 17 | 18005397659 |
| 18 | 74340087665 |
| 19 | 306933036933 |
| 20 | 1267255479837 |
| 21 | 5232203898902 |
| 22 | 21602557380388 |
| 23 | 89191955117072 |
[2,12,51,182,753,3061,12503,51668,213279,880209, 3634766,15007471,61961064,255823889,1056237984, 4360961496,18005397659,74340087665,306933036933, 1267255479837,5232203898902,21602557380388, 89191955117072] |