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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | 2 |
| 5 | 6 |
| 6 | 4 |
| 7 | 20 |
| 8 | 10 |
| 9 | 70 |
| 10 | 28 |
| 11 | 252 |
| 12 | 84 |
| 13 | 924 |
| 14 | 264 |
| 15 | 3432 |
| 16 | 858 |
| 17 | 12870 |
| 18 | 2860 |
| 19 | 48620 |
| 20 | 9724 |
| 21 | 184756 |
| 22 | 33592 |
| 23 | 705432 |
| 24 | 117572 |
| 25 | 2704156 |
| 26 | 416024 |
| 27 | 10400600 |
| 28 | 1485800 |
| 29 | 40116600 |
| 30 | 5348880 |
| 31 | 155117520 |
| 32 | 19389690 |
| 33 | 601080390 |
| 34 | 70715340 |
| 35 | 2333606220 |
| 36 | 259289580 |
| 37 | 9075135300 |
[1,1,2,2,2,6,4,20,10,70,28,252,84,924,264,3432, 858,12870,2860,48620,9724,184756,33592,705432, 117572,2704156,416024,10400600,1485800,40116600, 5348880,155117520,19389690,601080390,70715340, 2333606220,259289580,9075135300] |