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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 9 |
| 6 | 20 |
| 7 | 48 |
| 8 | 115 |
| 9 | 286 |
| 10 | 719 |
| 11 | 1842 |
| 12 | 4766 |
| 13 | 12486 |
| 14 | 32973 |
| 15 | 87811 |
| 16 | 235381 |
| 17 | 634847 |
| 18 | 1721159 |
| 19 | 4688676 |
| 20 | 12826228 |
| 21 | 35221832 |
| 22 | 97055181 |
| 23 | 268282855 |
| 24 | 743724984 |
| 25 | 2067174645 |
| 26 | 5759636510 |
| 27 | 16083734329 |
| 28 | 45007066269 |
| 29 | 126186554308 |
| 30 | 354426847597 |
| 31 | 997171512998 |
[0,1,1,2,4,9,20,48,115,286,719,1842,4766,12486, 32973,87811,235381,634847,1721159,4688676, 12826228,35221832,97055181,268282855,743724984, 2067174645,5759636510,16083734329,45007066269, 126186554308,354426847597,997171512998] |