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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 14 |
| 3 | 81 |
| 4 | 551 |
| 5 | 4266 |
| 6 | 36803 |
| 7 | 348543 |
| 8 | 3583484 |
| 9 | 39652659 |
| 10 | 468970211 |
| 11 | 5894584812 |
| 12 | 78366374813 |
| 13 | 1097537989671 |
| 14 | 16136598952718 |
| 15 | 248309032411485 |
| 16 | 3988468487017379 |
| 17 | 66715970326561170 |
| 18 | 1159712730763363991 |
| 19 | 20909709414253764819 |
| 20 | 390374806223071148084 |
| 21 | 7534929383736826736007 |
[1,3,14,81,551,4266,36803,348543,3583484,39652659, 468970211,5894584812,78366374813,1097537989671, 16136598952718,248309032411485,3988468487017379, 66715970326561170,1159712730763363991, 20909709414253764819,390374806223071148084, 7534929383736826736007] |