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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 40 |
| 4 | 217 |
| 5 | 1158 |
| 6 | 6150 |
| 7 | 32656 |
| 8 | 173719 |
| 9 | 926664 |
| 10 | 4958556 |
| 11 | 26619438 |
| 12 | 143365880 |
| 13 | 774562478 |
| 14 | 4197344582 |
| 15 | 22810572062 |
| 16 | 124300860689 |
| 17 | 679081142350 |
| 18 | 3718894341450 |
| 19 | 20412141531664 |
| 20 | 112276061739814 |
| 21 | 618806031336236 |
| 22 | 3416954495002676 |
[1,7,40,217,1158,6150,32656,173719,926664,4958556, 26619438,143365880,774562478,4197344582, 22810572062,124300860689,679081142350, 3718894341450,20412141531664,112276061739814, 618806031336236,3416954495002676] |