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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 7 |
| 6 | 12 |
| 7 | 47 |
| 8 | 107 |
| 9 | 337 |
| 10 | 868 |
| 11 | 2520 |
| 12 | 6808 |
| 13 | 19192 |
| 14 | 52756 |
| 15 | 147185 |
| 16 | 407069 |
| 17 | 1131599 |
| 18 | 3136292 |
| 19 | 8707655 |
| 20 | 24151335 |
| 21 | 67025633 |
| 22 | 185946904 |
| 23 | 515971328 |
| 24 | 1431563056 |
| 25 | 3972149312 |
| 26 | 11021051864 |
| 27 | 30579529249 |
| 28 | 84846231017 |
| 29 | 235416993159 |
| 30 | 653192251196 |
[0,0,1,1,7,12,47,107,337,868,2520,6808,19192, 52756,147185,407069,1131599,3136292,8707655, 24151335,67025633,185946904,515971328,1431563056, 3972149312,11021051864,30579529249,84846231017, 235416993159,653192251196] |