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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 20 |
| 5 | 71 |
| 6 | 262 |
| 7 | 994 |
| 8 | 3852 |
| 9 | 15183 |
| 10 | 60686 |
| 11 | 245410 |
| 12 | 1002300 |
| 13 | 4128448 |
| 14 | 17129920 |
| 15 | 71529800 |
| 16 | 300355184 |
| 17 | 1267386163 |
| 18 | 5371101382 |
| 19 | 22850230642 |
| 20 | 97546995260 |
| 21 | 417717017392 |
| 22 | 1793765580704 |
| 23 | 7722405668232 |
| 24 | 33323153856880 |
| 25 | 144099312039391 |
| 26 | 624347587536782 |
| 27 | 2710036186345914 |
| 28 | 11782865084403212 |
| 29 | 51310167663855675 |
| 30 | 223762749750806942 |
| 31 | 977155903597684074 |
| 32 | 4272633455348970588 |
| 33 | 18704696346822470087 |
| 34 | 81978422471165944654 |
[1,2,6,20,71,262,994,3852,15183,60686,245410, 1002300,4128448,17129920,71529800,300355184, 1267386163,5371101382,22850230642,97546995260, 417717017392,1793765580704,7722405668232, 33323153856880,144099312039391,624347587536782, 2710036186345914,11782865084403212, 51310167663855675,223762749750806942, 977155903597684074,4272633455348970588, 18704696346822470087,81978422471165944654] |