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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 49 |
| 6 | 240 |
| 7 | 1259 |
| 8 | 7570 |
| 9 | 47996 |
| 10 | 319518 |
| 11 | 2199295 |
| 12 | 15571610 |
| 13 | 112773478 |
| 14 | 832809504 |
| 15 | 6253673323 |
| 16 | 47650870538 |
| 17 | 367784975116 |
| 18 | 2871331929096 |
| 19 | 22647192990256 |
| 20 | 180277915464664 |
| 21 | 1447060793168493 |
| 22 | 11703567787559680 |
| 23 | 95312765368320637 |
| 24 | 781151020141584190 |
[1,1,2,5,14,49,240,1259,7570,47996,319518,2199295, 15571610,112773478,832809504,6253673323, 47650870538,367784975116,2871331929096, 22647192990256,180277915464664,1447060793168493, 11703567787559680,95312765368320637, 781151020141584190] |