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| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 1 |
| 6 | 3 |
| 7 | 8 |
| 8 | 21 |
| 9 | 56 |
| 10 | 152 |
| 11 | 413 |
| 12 | 1131 |
| 13 | 3113 |
| 14 | 8603 |
| 15 | 23861 |
| 16 | 66386 |
| 17 | 185190 |
| 18 | 517807 |
| 19 | 1450836 |
| 20 | 4072474 |
| 21 | 11450141 |
| 22 | 32240466 |
| 23 | 90901507 |
| 24 | 256605905 |
| 25 | 725176409 |
| 26 | 2051455548 |
| 27 | 5808817638 |
| 28 | 16462274560 |
| 29 | 46691893949 |
| 30 | 132531324274 |
| 31 | 376443234567 |
| 32 | 1069953746735 |
| 33 | 3042969864371 |
[1,1,3,8,21,56,152,413,1131,3113,8603,23861,66386, 185190,517807,1450836,4072474,11450141,32240466, 90901507,256605905,725176409,2051455548, 5808817638,16462274560,46691893949,132531324274, 376443234567,1069953746735,3042969864371] |