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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 19 |
| 4 | 94 |
| 5 | 396 |
| 6 | 1870 |
| 7 | 8541 |
| 8 | 40284 |
| 9 | 189274 |
| 10 | 899260 |
| 11 | 4281168 |
| 12 | 20487156 |
| 13 | 98299384 |
| 14 | 473118174 |
| 15 | 2282322211 |
| 16 | 11034087438 |
| 17 | 53443135944 |
| 18 | 259283934816 |
| 19 | 1259795078566 |
| 20 | 6129223177272 |
| 21 | 29856164309124 |
| 22 | 145592506783224 |
| 23 | 710686739172096 |
| 24 | 3472285996766556 |
| 25 | 16979257639328076 |
[1,1,6,19,94,396,1870,8541,40284,189274,899260, 4281168,20487156,98299384,473118174,2282322211, 11034087438,53443135944,259283934816, 1259795078566,6129223177272,29856164309124, 145592506783224,710686739172096,3472285996766556, 16979257639328076] |