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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 11 |
| 4 | 24 |
| 5 | 56 |
| 6 | 121 |
| 7 | 272 |
| 8 | 612 |
| 9 | 1373 |
| 10 | 3082 |
| 11 | 6914 |
| 12 | 15501 |
| 13 | 34784 |
| 14 | 78034 |
| 15 | 175061 |
| 16 | 392748 |
| 17 | 881084 |
| 18 | 1976647 |
| 19 | 4434500 |
| 20 | 9948474 |
| 21 | 22318763 |
| 22 | 50070676 |
| 23 | 112330190 |
| 24 | 252005457 |
| 25 | 565357670 |
| 26 | 1268342734 |
| 27 | 2845443827 |
| 28 | 6383566410 |
| 29 | 14321112518 |
| 30 | 32128477051 |
[2,4,11,24,56,121,272,612,1373,3082,6914,15501, 34784,78034,175061,392748,881084,1976647,4434500, 9948474,22318763,50070676,112330190,252005457, 565357670,1268342734,2845443827,6383566410, 14321112518,32128477051] |