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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 3 |
| 3 | 3 |
| 4 | 4 |
| 5 | 32 |
| 6 | 92 |
| 7 | 270 |
| 8 | 1262 |
| 9 | 3561 |
| 10 | 13976 |
| 11 | 48859 |
| 12 | 173602 |
| 13 | 622502 |
| 14 | 2233811 |
| 15 | 7882027 |
| 16 | 28343929 |
| 17 | 100832747 |
| 18 | 360076171 |
| 19 | 1284751998 |
| 20 | 4584944102 |
| 21 | 16356781324 |
| 22 | 58381988677 |
| 23 | 208293028674 |
| 24 | 743376640816 |
| 25 | 2652427350327 |
| 26 | 9465170814378 |
[0,3,3,4,32,92,270,1262,3561,13976,48859,173602, 622502,2233811,7882027,28343929,100832747, 360076171,1284751998,4584944102,16356781324, 58381988677,208293028674,743376640816, 2652427350327,9465170814378] |