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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 11 |
| 3 | 41 |
| 4 | 176 |
| 5 | 606 |
| 6 | 2391 |
| 7 | 8091 |
| 8 | 28636 |
| 9 | 95056 |
| 10 | 316048 |
| 11 | 1014240 |
| 12 | 3237325 |
| 13 | 10082015 |
| 14 | 31109500 |
| 15 | 94352346 |
| 16 | 283209381 |
| 17 | 838650191 |
| 18 | 2458835711 |
| 19 | 7127912979 |
| 20 | 20471486368 |
| 21 | 58224189612 |
| 22 | 164181018330 |
| 23 | 458982667630 |
| 24 | 1273039111210 |
| 25 | 3503609456548 |
| 26 | 9572771822745 |
| 27 | 25971150308985 |
[1,1,11,41,176,606,2391,8091,28636,95056,316048, 1014240,3237325,10082015,31109500,94352346, 283209381,838650191,2458835711,7127912979, 20471486368,58224189612,164181018330,458982667630, 1273039111210,3503609456548,9572771822745, 25971150308985] |