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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 17 |
| 3 | 153 |
| 4 | 1621 |
| 5 | 18732 |
| 6 | 229103 |
| 7 | 2915498 |
| 8 | 38204497 |
| 9 | 512027945 |
| 10 | 6985933889 |
| 11 | 96705749625 |
| 12 | 1354868839933 |
| 13 | 19175008086962 |
| 14 | 273731258980839 |
| 15 | 3936883123412972 |
| 16 | 56991044183321197 |
| 17 | 829750943505927435 |
| 18 | 12142121554514962205 |
| 19 | 178488780583916045949 |
[1,3,17,153,1621,18732,229103,2915498,38204497, 512027945,6985933889,96705749625,1354868839933, 19175008086962,273731258980839,3936883123412972, 56991044183321197,829750943505927435, 12142121554514962205,178488780583916045949] |