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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 7 |
| 2 | 51 |
| 3 | 381 |
| 4 | 2889 |
| 5 | 22095 |
| 6 | 169803 |
| 7 | 1308501 |
| 8 | 10098513 |
| 9 | 78001623 |
| 10 | 602768547 |
| 11 | 4659169005 |
| 12 | 36018666009 |
| 13 | 278471414943 |
| 14 | 2153041001019 |
| 15 | 16646935319109 |
| 16 | 128712870795681 |
| 17 | 995205584017575 |
| 18 | 7694942271953427 |
| 19 | 59497522990861149 |
[1,7,51,381,2889,22095,169803,1308501,10098513, 78001623,602768547,4659169005,36018666009, 278471414943,2153041001019,16646935319109, 128712870795681,995205584017575,7694942271953427, 59497522990861149] |