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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 53 |
| 5 | 309 |
| 6 | 2359 |
| 7 | 18367 |
| 8 | 168489 |
| 9 | 1690217 |
| 10 | 19416491 |
| 11 | 233144691 |
| 12 | 3187062493 |
| 13 | 44901291421 |
| 14 | 700058510943 |
| 15 | 11509417045799 |
| 16 | 200586478516049 |
| 17 | 3680237286827217 |
| 18 | 72326917665944659 |
| 19 | 1467930587827522267 |
| 20 | 31855597406715020421 |
| 21 | 718484783876745110021 |
| 22 | 16993553696264436052103 |
[1,1,3,11,53,309,2359,18367,168489,1690217, 19416491,233144691,3187062493,44901291421, 700058510943,11509417045799,200586478516049, 3680237286827217,72326917665944659, 1467930587827522267,31855597406715020421, 718484783876745110021,16993553696264436052103] |