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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 10 |
| 6 | 22 |
| 7 | 56 |
| 8 | 136 |
| 9 | 348 |
| 10 | 890 |
| 11 | 2332 |
| 12 | 6136 |
| 13 | 16380 |
| 14 | 43988 |
| 15 | 119170 |
| 16 | 324720 |
| 17 | 890290 |
| 18 | 2452752 |
| 19 | 6789308 |
| 20 | 18868520 |
| 21 | 52635730 |
| 22 | 147323176 |
| 23 | 413618614 |
| 24 | 1164510896 |
| 25 | 3287073450 |
| 26 | 9300500508 |
| 27 | 26372968632 |
| 28 | 74937133488 |
| 29 | 213333642442 |
| 30 | 608400799010 |
| 31 | 1737954608280 |
[1,1,2,4,10,22,56,136,348,890,2332,6136,16380, 43988,119170,324720,890290,2452752,6789308, 18868520,52635730,147323176,413618614,1164510896, 3287073450,9300500508,26372968632,74937133488, 213333642442,608400799010,1737954608280] |