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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 8 |
| 6 | 26 |
| 7 | 89 |
| 8 | 324 |
| 9 | 1225 |
| 10 | 4786 |
| 11 | 19170 |
| 12 | 78408 |
| 13 | 326275 |
| 14 | 1377772 |
| 15 | 5891401 |
| 16 | 25467509 |
| 17 | 111144579 |
| 18 | 489145720 |
| 19 | 2168854885 |
| 20 | 9681072845 |
| 21 | 43473716527 |
| 22 | 196286934526 |
| 23 | 890640262188 |
| 24 | 4059500301390 |
| 25 | 18579693200838 |
| 26 | 85360357637580 |
| 27 | 393548515741979 |
| 28 | 1820335724153452 |
| 29 | 8445294476235727 |
| 30 | 39291407672079211 |
[1,1,1,1,3,8,26,89,324,1225,4786,19170,78408, 326275,1377772,5891401,25467509,111144579, 489145720,2168854885,9681072845,43473716527, 196286934526,890640262188,4059500301390, 18579693200838,85360357637580,393548515741979, 1820335724153452,8445294476235727, 39291407672079211] |