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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 12 |
| 4 | 27 |
| 5 | 62 |
| 6 | 141 |
| 7 | 320 |
| 8 | 727 |
| 9 | 1650 |
| 10 | 3745 |
| 11 | 8500 |
| 12 | 19291 |
| 13 | 43782 |
| 14 | 99365 |
| 15 | 225512 |
| 16 | 511807 |
| 17 | 1161562 |
| 18 | 2636201 |
| 19 | 5982940 |
| 20 | 13578467 |
| 21 | 30816750 |
| 22 | 69939565 |
| 23 | 158730000 |
| 24 | 360242631 |
| 25 | 817581762 |
| 26 | 1855527025 |
| 27 | 4211175812 |
| 28 | 9557393387 |
| 29 | 21690799062 |
| 30 | 49227937461 |
| 31 | 111724322360 |
[1,2,5,12,27,62,141,320,727,1650,3745,8500,19291, 43782,99365,225512,511807,1161562,2636201,5982940, 13578467,30816750,69939565,158730000,360242631, 817581762,1855527025,4211175812,9557393387, 21690799062,49227937461,111724322360] |