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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 2 |
| 4 | 3 |
| 5 | 6 |
| 6 | 15 |
| 7 | 22 |
| 8 | 41 |
| 9 | 72 |
| 10 | 129 |
| 11 | 213 |
| 12 | 395 |
| 13 | 660 |
| 14 | 1173 |
| 15 | 2031 |
| 16 | 3582 |
| 17 | 6188 |
| 18 | 10927 |
| 19 | 18977 |
| 20 | 33333 |
| 21 | 58153 |
| 22 | 101954 |
| 23 | 178044 |
| 24 | 312080 |
| 25 | 545475 |
| 26 | 955317 |
| 27 | 1670990 |
| 28 | 2925711 |
| 29 | 5118558 |
| 30 | 8960938 |
| 31 | 15680072 |
| 32 | 27447344 |
| 33 | 48033498 |
| 34 | 84076139 |
| 35 | 147142492 |
| 36 | 257546234 |
| 37 | 450748482 |
| 38 | 788937188 |
[0,0,2,3,6,15,22,41,72,129,213,395,660,1173,2031, 3582,6188,10927,18977,33333,58153,101954,178044, 312080,545475,955317,1670990,2925711,5118558, 8960938,15680072,27447344,48033498,84076139, 147142492,257546234,450748482,788937188] |