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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 22 |
| 5 | 54 |
| 6 | 136 |
| 7 | 340 |
| 8 | 857 |
| 9 | 2164 |
| 10 | 5481 |
| 11 | 13911 |
| 12 | 35379 |
| 13 | 90124 |
| 14 | 229913 |
| 15 | 587254 |
| 16 | 1501615 |
| 17 | 3843314 |
| 18 | 9845118 |
| 19 | 25238541 |
| 20 | 64744455 |
| 21 | 166190960 |
| 22 | 426829202 |
| 23 | 1096784835 |
| 24 | 2819620836 |
| 25 | 7251796132 |
| 26 | 18658280277 |
| 27 | 48023738374 |
| 28 | 123648031266 |
| 29 | 318460151301 |
| 30 | 820446813941 |
[1,1,3,9,22,54,136,340,857,2164,5481,13911,35379, 90124,229913,587254,1501615,3843314,9845118, 25238541,64744455,166190960,426829202,1096784835, 2819620836,7251796132,18658280277,48023738374, 123648031266,318460151301,820446813941] |