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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 54 |
| 3 | 1334 |
| 4 | 48816 |
| 5 | 2383682 |
| 6 | 146036788 |
| 7 | 10781227690 |
| 8 | 932243805168 |
| 9 | 92452039842626 |
| 10 | 10346916215343564 |
| 11 | 1290195352404492602 |
| 12 | 177396099439904780200 |
| 13 | 26665611450484642809058 |
| 14 | 4350590232650155748720484 |
| 15 | 765717105431099707449714218 |
[1,4,54,1334,48816,2383682,146036788,10781227690, 932243805168,92452039842626,10346916215343564, 1290195352404492602,177396099439904780200, 26665611450484642809058,4350590232650155748720484, 765717105431099707449714218] |