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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 26 |
| 5 | 89 |
| 6 | 301 |
| 7 | 1113 |
| 8 | 4103 |
| 9 | 15713 |
| 10 | 61009 |
| 11 | 239022 |
| 12 | 957052 |
| 13 | 3842957 |
| 14 | 15682418 |
| 15 | 64327986 |
| 16 | 266060448 |
| 17 | 1109178457 |
| 18 | 4642255214 |
| 19 | 19584021301 |
| 20 | 82870650100 |
| 21 | 352746311724 |
| 22 | 1507055476582 |
| 23 | 6462776373617 |
| 24 | 27830950502522 |
| 25 | 120152552294094 |
| 26 | 520749391990068 |
| 27 | 2262072675615448 |
| 28 | 9856375982880292 |
[1,1,3,8,26,89,301,1113,4103,15713,61009,239022, 957052,3842957,15682418,64327986,266060448, 1109178457,4642255214,19584021301,82870650100, 352746311724,1507055476582,6462776373617, 27830950502522,120152552294094,520749391990068, 2262072675615448,9856375982880292] |