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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 50 |
| 5 | 179 |
| 6 | 844 |
| 7 | 3400 |
| 8 | 16351 |
| 9 | 70268 |
| 10 | 341854 |
| 11 | 1528459 |
| 12 | 7490503 |
| 13 | 34379761 |
| 14 | 169311818 |
| 15 | 791428328 |
| 16 | 3910978136 |
| 17 | 18525118321 |
| 18 | 91772597075 |
| 19 | 439023657803 |
| 20 | 2178920977547 |
| 21 | 10502920105982 |
| 22 | 52200231902042 |
| 23 | 253113688816381 |
| 24 | 1259356840268939 |
| 25 | 6135341868509264 |
| 26 | 30552135452224128 |
| 27 | 149410855632996375 |
[1,1,4,11,50,179,844,3400,16351,70268,341854, 1528459,7490503,34379761,169311818,791428328, 3910978136,18525118321,91772597075,439023657803, 2178920977547,10502920105982,52200231902042, 253113688816381,1259356840268939,6135341868509264, 30552135452224128,149410855632996375] |