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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 51 |
| 3 | 900 |
| 4 | 16455 |
| 5 | 307833 |
| 6 | 5850000 |
| 7 | 112445112 |
| 8 | 2180050215 |
| 9 | 42552000000 |
| 10 | 835075676361 |
| 11 | 16461248223588 |
| 12 | 325696500000000 |
| 13 | 6464447754891285 |
| 14 | 128654307202482420 |
| 15 | 2566472490000000000 |
| 16 | 51302899404879842343 |
| 17 | 1027391467409893403745 |
| 18 | 20607804108000000000000 |
[1,3,51,900,16455,307833,5850000,112445112, 2180050215,42552000000,835075676361, 16461248223588,325696500000000,6464447754891285, 128654307202482420,2566472490000000000, 51302899404879842343,1027391467409893403745, 20607804108000000000000] |