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| n | a(n) |
|---|---|
| 3 | 17 |
| 4 | 41 |
| 5 | 1787 |
| 6 | 37 |
| 7 | 1011749 |
| 8 | -1 |
| 9 | 8070191 |
| 10 | 18919 |
| 11 | 31783046759 |
| 12 | -1 |
| 13 | 107 |
| 14 | 13588859 |
| 15 | -1 |
| 16 | 906611171779 |
| 17 | 106661882252960131 |
| 18 | 9883 |
| 19 | 40487203 |
| 20 | 173127971 |
| 21 | 5664484284773 |
| 22 | 696222287901816728317439 |
| 23 | -1 |
| 24 | 101 |
| 25 | 97453813 |
| 26 | -1 |
| 27 | 28631342754671 |
| 28 | 15215869393552811003 |
| 29 | 629657070248572792452284791790843 |
| 30 | -1 |
| 31 | 32233 |
| 32 | 123323 |
| 33 | 334444555566656663 |
| 34 | 122334444555553 |
| 35 | 122334444555566566663 |
| 36 | 1223334444555556666677767777 |
| 37 | 22333444455555666666777777788888898999999989 |
| 38 | -1 |
[17,41,1787,37,1011749,-1,8070191,18919, 31783046759,-1,107,13588859,-1,906611171779, 106661882252960131,9883,40487203,173127971, 5664484284773,696222287901816728317439,-1,101, 97453813,-1,28631342754671,15215869393552811003, 629657070248572792452284791790843,-1,32233,123323, 334444555566656663,122334444555553, 122334444555566566663, 1223334444555556666677767777, 22333444455555666666777777788888898999999989,-1] |