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| n | a(n) |
|---|---|
| 3 | 0 |
| 4 | 2 |
| 5 | 2 |
| 6 | 4 |
| 7 | 14 |
| 8 | 30 |
| 9 | 46 |
| 10 | 141 |
| 11 | 313 |
| 12 | 642 |
| 13 | 1586 |
| 14 | 3566 |
| 15 | 7827 |
| 16 | 18673 |
| 17 | 43608 |
| 18 | 101775 |
| 19 | 248214 |
| 20 | 606621 |
| 21 | 1511160 |
| 22 | 3855263 |
| 23 | 9905069 |
| 24 | 25825329 |
| 25 | 67971371 |
| 26 | 179759191 |
| 27 | 477647229 |
| 28 | 1271389790 |
| 29 | 3384877996 |
| 30 | 9010240169 |
| 31 | 23958321608 |
[0,2,2,4,14,30,46,141,313,642,1586,3566,7827, 18673,43608,101775,248214,606621,1511160,3855263, 9905069,25825329,67971371,179759191,477647229, 1271389790,3384877996,9010240169,23958321608] |