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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 11 |
| 4 | 47 |
| 5 | 143 |
| 6 | 599 |
| 7 | 2025 |
| 8 | 8577 |
| 9 | 30813 |
| 10 | 130227 |
| 11 | 487643 |
| 12 | 2080201 |
| 13 | 7947799 |
| 14 | 34171305 |
| 15 | 133054913 |
| 16 | 573451125 |
| 17 | 2267413293 |
| 18 | 9813947025 |
| 19 | 39208267881 |
| 20 | 170253111501 |
| 21 | 686862364999 |
| 22 | 2988364706025 |
| 23 | 12153303057065 |
| 24 | 52998289616957 |
| 25 | 216930771161139 |
| 26 | 947653513891821 |
| 27 | 3902052543886669 |
[1,1,5,11,47,143,599,2025,8577,30813,130227, 487643,2080201,7947799,34171305,133054913, 573451125,2267413293,9813947025,39208267881, 170253111501,686862364999,2988364706025, 12153303057065,52998289616957,216930771161139, 947653513891821,3902052543886669] |