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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 9 |
| 6 | 21 |
| 7 | 51 |
| 8 | 128 |
| 9 | 329 |
| 10 | 861 |
| 11 | 2285 |
| 12 | 6132 |
| 13 | 16606 |
| 14 | 45313 |
| 15 | 124446 |
| 16 | 343680 |
| 17 | 953753 |
| 18 | 2658133 |
| 19 | 7436541 |
| 20 | 20875972 |
| 21 | 58783892 |
| 22 | 165989825 |
| 23 | 469903672 |
| 24 | 1333359488 |
| 25 | 3791535934 |
| 26 | 10802911297 |
| 27 | 30836181436 |
| 28 | 88169413364 |
| 29 | 252500533673 |
| 30 | 724182805389 |
| 31 | 2079862921763 |
| 32 | 5981150599872 |
[1,2,4,9,21,51,128,329,861,2285,6132,16606,45313, 124446,343680,953753,2658133,7436541,20875972, 58783892,165989825,469903672,1333359488, 3791535934,10802911297,30836181436,88169413364, 252500533673,724182805389,2079862921763, 5981150599872] |