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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 7 |
| 3 | 12 |
| 4 | 25 |
| 5 | 51 |
| 6 | 121 |
| 7 | 272 |
| 8 | 656 |
| 9 | 1563 |
| 10 | 3794 |
| 11 | 9193 |
| 12 | 22529 |
| 13 | 55189 |
| 14 | 136025 |
| 15 | 335942 |
| 16 | 832605 |
| 17 | 2068070 |
| 18 | 5150558 |
| 19 | 12852754 |
| 20 | 32139908 |
| 21 | 80509629 |
| 22 | 202016993 |
| 23 | 507669052 |
| 24 | 1277595853 |
| 25 | 3219366640 |
| 26 | 8122296152 |
[1,4,7,12,25,51,121,272,656,1563,3794,9193,22529, 55189,136025,335942,832605,2068070,5150558, 12852754,32139908,80509629,202016993,507669052, 1277595853,3219366640,8122296152] |