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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 20 |
| 4 | 56 |
| 5 | 141 |
| 6 | 328 |
| 7 | 732 |
| 8 | 1584 |
| 9 | 3339 |
| 10 | 6894 |
| 11 | 14018 |
| 12 | 28132 |
| 13 | 55819 |
| 14 | 109668 |
| 15 | 213711 |
| 16 | 413520 |
| 17 | 795041 |
| 18 | 1519632 |
| 19 | 2890050 |
| 20 | 5471864 |
| 21 | 10317249 |
| 22 | 19378344 |
| 23 | 36273795 |
| 24 | 67690580 |
| 25 | 125950933 |
| 26 | 233715516 |
| 27 | 432618758 |
| 28 | 798985468 |
| 29 | 1472443438 |
| 30 | 2708024388 |
| 31 | 4971153360 |
| 32 | 9109787516 |
| 33 | 16666330020 |
| 34 | 30442830024 |
| 35 | 55525884185 |
| 36 | 101137051948 |
| 37 | 183972829656 |
[1,6,20,56,141,328,732,1584,3339,6894,14018,28132, 55819,109668,213711,413520,795041,1519632,2890050, 5471864,10317249,19378344,36273795,67690580, 125950933,233715516,432618758,798985468, 1472443438,2708024388,4971153360,9109787516, 16666330020,30442830024,55525884185,101137051948, 183972829656] |