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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 16 |
| 3 | 97 |
| 4 | 553 |
| 5 | 3668 |
| 6 | 24370 |
| 7 | 145761 |
| 8 | 905291 |
| 9 | 5678975 |
| 10 | 35331350 |
| 11 | 219280373 |
| 12 | 1365001746 |
| 13 | 8497501967 |
| 14 | 52836680760 |
| 15 | 328652764556 |
| 16 | 2044693862684 |
| 17 | 12719074189744 |
| 18 | 79117923662603 |
| 19 | 492169411569361 |
| 20 | 3061623752650382 |
[1,16,97,553,3668,24370,145761,905291,5678975, 35331350,219280373,1365001746,8497501967, 52836680760,328652764556,2044693862684, 12719074189744,79117923662603,492169411569361, 3061623752650382] |