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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 0 |
| 5 | 6 |
| 6 | 5 |
| 7 | 36 |
| 8 | 84 |
| 9 | 309 |
| 10 | 890 |
| 11 | 3163 |
| 12 | 9835 |
| 13 | 32979 |
| 14 | 108252 |
| 15 | 360696 |
| 16 | 1192410 |
| 17 | 3984552 |
| 18 | 13276769 |
| 19 | 44371368 |
| 20 | 148402665 |
| 21 | 497072593 |
| 22 | 1665557619 |
| 23 | 5586863093 |
| 24 | 18750662066 |
| 25 | 62968243731 |
| 26 | 211565969511 |
| 27 | 711187790166 |
| 28 | 2391640404772 |
| 29 | 8045964959333 |
| 30 | 27077856222546 |
[1,0,1,0,6,5,36,84,309,890,3163,9835,32979,108252, 360696,1192410,3984552,13276769,44371368, 148402665,497072593,1665557619,5586863093, 18750662066,62968243731,211565969511,711187790166, 2391640404772,8045964959333,27077856222546] |