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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 2 |
| 5 | 4 |
| 6 | 9 |
| 7 | 45 |
| 8 | 164 |
| 9 | 546 |
| 10 | 1493 |
| 11 | 3944 |
| 12 | 10588 |
| 13 | 32997 |
| 14 | 112945 |
| 15 | 396404 |
| 16 | 1330461 |
| 17 | 4265180 |
| 18 | 13292275 |
| 19 | 41778612 |
| 20 | 135378928 |
| 21 | 452828655 |
| 22 | 1534394542 |
| 23 | 5175561385 |
| 24 | 17246318586 |
| 25 | 56998526633 |
| 26 | 188492707958 |
| 27 | 628391304843 |
| 28 | 2115131897264 |
| 29 | 7162685531894 |
| 30 | 24280930956521 |
| 31 | 82152859633099 |
[1,1,2,2,4,9,45,164,546,1493,3944,10588,32997, 112945,396404,1330461,4265180,13292275,41778612, 135378928,452828655,1534394542,5175561385, 17246318586,56998526633,188492707958,628391304843, 2115131897264,7162685531894,24280930956521, 82152859633099] |