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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 19 |
| 2 | 342 |
| 3 | 6156 |
| 4 | 110808 |
| 5 | 1994544 |
| 6 | 35901621 |
| 7 | 646226100 |
| 8 | 11632014567 |
| 9 | 209375268012 |
| 10 | 3768736928724 |
| 11 | 67836942598176 |
| 12 | 1221059168656830 |
| 13 | 21978960670333953 |
| 14 | 395619413496128064 |
| 15 | 7121115628832971863 |
| 16 | 128179472668131616290 |
| 17 | 2307219552362877498072 |
| 18 | 41529754741525340825124 |
[1,19,342,6156,110808,1994544,35901621,646226100, 11632014567,209375268012,3768736928724, 67836942598176,1221059168656830,21978960670333953, 395619413496128064,7121115628832971863, 128179472668131616290,2307219552362877498072, 41529754741525340825124] |