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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 20 |
| 4 | 55 |
| 5 | 142 |
| 6 | 322 |
| 7 | 779 |
| 8 | 1608 |
| 9 | 3894 |
| 10 | 7370 |
| 11 | 18372 |
| 12 | 33137 |
| 13 | 81512 |
| 14 | 149694 |
| 15 | 353224 |
| 16 | 641461 |
| 17 | 1570836 |
| 18 | 2684928 |
| 19 | 6642915 |
| 20 | 11795178 |
| 21 | 28133846 |
| 22 | 46768200 |
| 23 | 125433400 |
| 24 | 197654545 |
| 25 | 485749918 |
| 26 | 893864394 |
| 27 | 2066417482 |
| 28 | 3385115393 |
| 29 | 8975476976 |
| 30 | 14384181908 |
| 31 | 35478028091 |
| 32 | 61940000322 |
[1,6,20,55,142,322,779,1608,3894,7370,18372,33137, 81512,149694,353224,641461,1570836,2684928, 6642915,11795178,28133846,46768200,125433400, 197654545,485749918,893864394,2066417482, 3385115393,8975476976,14384181908,35478028091, 61940000322] |