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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 12 |
| 4 | 26 |
| 5 | 60 |
| 6 | 144 |
| 7 | 324 |
| 8 | 728 |
| 9 | 1602 |
| 10 | 3576 |
| 11 | 7808 |
| 12 | 17068 |
| 13 | 36908 |
| 14 | 79520 |
| 15 | 170704 |
| 16 | 364794 |
| 17 | 777036 |
| 18 | 1649456 |
| 19 | 3491188 |
| 20 | 7367544 |
| 21 | 15513336 |
| 22 | 32584648 |
| 23 | 68307264 |
| 24 | 142904080 |
| 25 | 298448914 |
| 26 | 622235060 |
| 27 | 1295320004 |
| 28 | 2692583916 |
| 29 | 5589586996 |
| 30 | 11588905844 |
| 31 | 23999052692 |
[1,2,4,12,26,60,144,324,728,1602,3576,7808,17068, 36908,79520,170704,364794,777036,1649456,3491188, 7367544,15513336,32584648,68307264,142904080, 298448914,622235060,1295320004,2692583916, 5589586996,11588905844,23999052692] |