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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 17 |
| 4 | 60 |
| 5 | 221 |
| 6 | 826 |
| 7 | 3229 |
| 8 | 12841 |
| 9 | 51669 |
| 10 | 210672 |
| 11 | 870069 |
| 12 | 3626280 |
| 13 | 15209165 |
| 14 | 64286104 |
| 15 | 273489917 |
| 16 | 1169463848 |
| 17 | 5022549846 |
| 18 | 21673068761 |
| 19 | 93901104376 |
| 20 | 408200562527 |
| 21 | 1780102962708 |
| 22 | 7787537166599 |
| 23 | 34163229720947 |
| 24 | 150234088468516 |
| 25 | 662220519961800 |
| 26 | 2925718885996118 |
| 27 | 12952307741949492 |
[1,2,5,17,60,221,826,3229,12841,51669,210672, 870069,3626280,15209165,64286104,273489917, 1169463848,5022549846,21673068761,93901104376, 408200562527,1780102962708,7787537166599, 34163229720947,150234088468516,662220519961800, 2925718885996118,12952307741949492] |