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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 2 |
| 4 | 17 |
| 5 | 94 |
| 6 | 464 |
| 7 | 2162 |
| 8 | 9743 |
| 9 | 42962 |
| 10 | 186584 |
| 11 | 801316 |
| 12 | 3412034 |
| 13 | 14430740 |
| 14 | 60700548 |
| 15 | 254180426 |
| 16 | 1060361147 |
| 17 | 4409342954 |
| 18 | 18285098288 |
| 19 | 75645143516 |
| 20 | 312286595342 |
| 21 | 1286827096964 |
| 22 | 5293833371408 |
| 23 | 21745951533236 |
| 24 | 89208948855542 |
| 25 | 365523293690804 |
| 26 | 1496048600896784 |
[0,0,2,17,94,464,2162,9743,42962,186584,801316, 3412034,14430740,60700548,254180426,1060361147, 4409342954,18285098288,75645143516,312286595342, 1286827096964,5293833371408,21745951533236, 89208948855542,365523293690804,1496048600896784] |