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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 10 |
| 6 | 27 |
| 7 | 62 |
| 8 | 165 |
| 9 | 423 |
| 10 | 1140 |
| 11 | 3060 |
| 12 | 8427 |
| 13 | 23218 |
| 14 | 64782 |
| 15 | 181370 |
| 16 | 511004 |
| 17 | 1444285 |
| 18 | 4097996 |
| 19 | 11656644 |
| 20 | 33243265 |
| 21 | 94992847 |
| 22 | 271953126 |
| 23 | 779790166 |
| 24 | 2239187466 |
| 25 | 6438039076 |
| 26 | 18532004323 |
| 27 | 53400606823 |
| 28 | 154024168401 |
| 29 | 444646510812 |
| 30 | 1284682242777 |
[1,0,1,2,5,10,27,62,165,423,1140,3060,8427,23218, 64782,181370,511004,1444285,4097996,11656644, 33243265,94992847,271953126,779790166,2239187466, 6438039076,18532004323,53400606823,154024168401, 444646510812,1284682242777] |