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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 31 |
| 5 | 82 |
| 6 | 241 |
| 7 | 664 |
| 8 | 1898 |
| 9 | 5316 |
| 10 | 15058 |
| 11 | 42374 |
| 12 | 119718 |
| 13 | 337432 |
| 14 | 952373 |
| 15 | 2685906 |
| 16 | 7578248 |
| 17 | 21376331 |
| 18 | 60306495 |
| 19 | 170120330 |
| 20 | 479922212 |
| 21 | 1353855927 |
| 22 | 3819280961 |
| 23 | 10774233218 |
| 24 | 30394408336 |
| 25 | 85743168417 |
| 26 | 241883489742 |
| 27 | 682358211402 |
| 28 | 1924947591447 |
| 29 | 5430317571250 |
| 30 | 15319043353639 |
[1,1,4,10,31,82,241,664,1898,5316,15058,42374, 119718,337432,952373,2685906,7578248,21376331, 60306495,170120330,479922212,1353855927, 3819280961,10774233218,30394408336,85743168417, 241883489742,682358211402,1924947591447, 5430317571250,15319043353639] |