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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 2 |
| 4 | 11 |
| 5 | 27 |
| 6 | 101 |
| 7 | 348 |
| 8 | 1237 |
| 9 | 4752 |
| 10 | 17552 |
| 11 | 69635 |
| 12 | 269504 |
| 13 | 1085729 |
| 14 | 4351437 |
| 15 | 17775548 |
| 16 | 72934213 |
| 17 | 302080006 |
| 18 | 1259717600 |
| 19 | 5283979096 |
| 20 | 22304022387 |
| 21 | 94582158638 |
| 22 | 403155327233 |
| 23 | 1725391432093 |
| 24 | 7415018474585 |
| 25 | 31980782229030 |
| 26 | 138409663709656 |
| 27 | 600908838337016 |
| 28 | 2616559379817830 |
[1,0,2,2,11,27,101,348,1237,4752,17552,69635, 269504,1085729,4351437,17775548,72934213, 302080006,1259717600,5283979096,22304022387, 94582158638,403155327233,1725391432093, 7415018474585,31980782229030,138409663709656, 600908838337016,2616559379817830] |