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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 41 |
| 6 | 200 |
| 7 | 1096 |
| 8 | 6440 |
| 9 | 40095 |
| 10 | 262298 |
| 11 | 1790395 |
| 12 | 12699751 |
| 13 | 93311273 |
| 14 | 708519038 |
| 15 | 5549751855 |
| 16 | 44780255681 |
| 17 | 371785828813 |
| 18 | 3173019719939 |
| 19 | 27813799706468 |
| 20 | 250222091088035 |
| 21 | 2308676057468240 |
| 22 | 21831456961064288 |
| 23 | 211449264040904335 |
| 24 | 2096345122112307560 |
| 25 | 21261235260097878478 |
| 26 | 220457711039776064974 |
| 27 | 2335722548273384751833 |
[1,1,1,3,9,41,200,1096,6440,40095,262298,1790395, 12699751,93311273,708519038,5549751855, 44780255681,371785828813,3173019719939, 27813799706468,250222091088035,2308676057468240, 21831456961064288,211449264040904335, 2096345122112307560,21261235260097878478, 220457711039776064974,2335722548273384751833] |