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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 9 |
| 4 | 31 |
| 5 | 40 |
| 6 | 671 |
| 7 | 711 |
| 8 | 2804 |
| 9 | 6319 |
| 10 | 21761 |
| 11 | 28080 |
| 12 | 471041 |
| 13 | 499121 |
| 14 | 1968404 |
| 15 | 4435929 |
| 16 | 15276191 |
| 17 | 19712120 |
| 18 | 330670111 |
| 19 | 350382231 |
| 20 | 1381816804 |
| 21 | 3114015839 |
| 22 | 10723864321 |
| 23 | 13837880160 |
| 24 | 232129946881 |
| 25 | 245967827041 |
| 26 | 970033428004 |
| 27 | 2186034683049 |
| 28 | 7528137477151 |
[1,1,4,9,31,40,671,711,2804,6319,21761,28080, 471041,499121,1968404,4435929,15276191,19712120, 330670111,350382231,1381816804,3114015839, 10723864321,13837880160,232129946881,245967827041, 970033428004,2186034683049,7528137477151] |