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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 26 |
| 5 | 75 |
| 6 | 154 |
| 7 | 269 |
| 8 | 1732 |
| 9 | 5764 |
| 10 | 15131 |
| 11 | 34345 |
| 12 | 135950 |
| 13 | 462186 |
| 14 | 1356284 |
| 15 | 3539433 |
| 16 | 11681091 |
| 17 | 38519022 |
| 18 | 118366429 |
| 19 | 334591568 |
| 20 | 1037603086 |
| 21 | 3309045401 |
| 22 | 10296063522 |
| 23 | 30414763937 |
| 24 | 92735958046 |
| 25 | 289374852696 |
| 26 | 899439481823 |
| 27 | 2716896548850 |
| 28 | 8270384213984 |
[1,1,1,1,26,75,154,269,1732,5764,15131,34345, 135950,462186,1356284,3539433,11681091,38519022, 118366429,334591568,1037603086,3309045401, 10296063522,30414763937,92735958046,289374852696, 899439481823,2716896548850,8270384213984] |