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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 21 |
| 6 | 45 |
| 7 | 99 |
| 8 | 225 |
| 9 | 513 |
| 10 | 1161 |
| 11 | 2619 |
| 12 | 5913 |
| 13 | 13365 |
| 14 | 30213 |
| 15 | 68283 |
| 16 | 154305 |
| 17 | 348705 |
| 18 | 788049 |
| 19 | 1780947 |
| 20 | 4024809 |
| 21 | 9095733 |
| 22 | 20555613 |
| 23 | 46454067 |
| 24 | 104982561 |
| 25 | 237252321 |
| 26 | 536171481 |
| 27 | 1211705163 |
| 28 | 2738358009 |
| 29 | 6188472981 |
| 30 | 13985460405 |
[1,1,1,3,9,21,45,99,225,513,1161,2619,5913,13365, 30213,68283,154305,348705,788049,1780947,4024809, 9095733,20555613,46454067,104982561,237252321, 536171481,1211705163,2738358009,6188472981, 13985460405] |