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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 2 |
| 6 | 4 |
| 7 | 8 |
| 8 | 36 |
| 9 | 40 |
| 10 | 49 |
| 11 | 126 |
| 12 | 121 |
| 13 | 440 |
| 14 | 2809 |
| 15 | 11395 |
| 16 | 32761 |
| 17 | 132183 |
| 18 | 881721 |
| 19 | 3015500 |
| 20 | 19642624 |
| 21 | 106493895 |
| 22 | 249987721 |
| 23 | 1257922092 |
| 24 | 4609187881 |
| 25 | 29262161844 |
| 26 | 189192811369 |
| 27 | 1068996265025 |
| 28 | 7388339422500 |
| 29 | 67416357342087 |
| 30 | 465724670229025 |
| 31 | 1979950199225010 |
[1,1,1,1,2,4,8,36,40,49,126,121,440,2809,11395, 32761,132183,881721,3015500,19642624,106493895, 249987721,1257922092,4609187881,29262161844, 189192811369,1068996265025,7388339422500, 67416357342087,465724670229025,1979950199225010] |