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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 10 |
| 3 | 1 |
| 4 | 55 |
| 5 | 2575 |
| 6 | 1 |
| 7 | 550 |
| 8 | 253000 |
| 9 | 250525000 |
| 10 | 1 |
| 11 | 5050 |
| 12 | 25007500 |
| 13 | 250025500000 |
| 14 | 2500000075000000 |
| 15 | 1 |
| 16 | 50500 |
| 17 | 2500300000 |
| 18 | 250002775000000 |
| 19 | 25000000255000000000 |
| 20 | 2500000000502500000000000 |
| 21 | 1 |
| 22 | 500500 |
| 23 | 250000750000 |
| 24 | 250000250500000000 |
| 25 | 250000000000750000000000 |
| 26 | 250000000000250500000000000000 |
| 27 | 250000000000000000750000000000000000 |
[1,1,10,1,55,2575,1,550,253000,250525000,1,5050, 25007500,250025500000,2500000075000000,1,50500, 2500300000,250002775000000,25000000255000000000, 2500000000502500000000000,1,500500,250000750000, 250000250500000000,250000000000750000000000, 250000000000250500000000000000, 250000000000000000750000000000000000] |