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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 46 |
| 5 | 167 |
| 6 | 724 |
| 7 | 2937 |
| 8 | 13198 |
| 9 | 56638 |
| 10 | 260681 |
| 11 | 1158673 |
| 12 | 5418236 |
| 13 | 24664374 |
| 14 | 116633536 |
| 15 | 540020796 |
| 16 | 2574876236 |
| 17 | 12072319038 |
| 18 | 57927952550 |
| 19 | 274200639772 |
| 20 | 1322301107301 |
| 21 | 6305857228733 |
| 22 | 30531313867656 |
| 23 | 146464682516223 |
| 24 | 711471159455107 |
| 25 | 3429482984153994 |
| 26 | 16704555180369196 |
| 27 | 80838570018888617 |
[1,1,4,11,46,167,724,2937,13198,56638,260681, 1158673,5418236,24664374,116633536,540020796, 2574876236,12072319038,57927952550,274200639772, 1322301107301,6305857228733,30531313867656, 146464682516223,711471159455107,3429482984153994, 16704555180369196,80838570018888617] |