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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 19 |
| 5 | 56 |
| 6 | 138 |
| 7 | 407 |
| 8 | 999 |
| 9 | 2851 |
| 10 | 7113 |
| 11 | 19702 |
| 12 | 49954 |
| 13 | 135461 |
| 14 | 347553 |
| 15 | 929567 |
| 16 | 2403759 |
| 17 | 6374236 |
| 18 | 16564458 |
| 19 | 43697227 |
| 20 | 113896339 |
| 21 | 299525051 |
| 22 | 782121453 |
| 23 | 2053027082 |
| 24 | 5366641794 |
| 25 | 14071792681 |
| 26 | 36807232413 |
| 27 | 96449857207 |
| 28 | 252375716899 |
| 29 | 661078086176 |
| 30 | 1730190463338 |
| 31 | 4531099045727 |
[1,1,3,7,19,56,138,407,999,2851,7113,19702,49954, 135461,347553,929567,2403759,6374236,16564458, 43697227,113896339,299525051,782121453,2053027082, 5366641794,14071792681,36807232413,96449857207, 252375716899,661078086176,1730190463338, 4531099045727] |