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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 9 |
| 4 | 34 |
| 5 | 103 |
| 6 | 399 |
| 7 | 1329 |
| 8 | 5420 |
| 9 | 19005 |
| 10 | 79683 |
| 11 | 292567 |
| 12 | 1246622 |
| 13 | 4721185 |
| 14 | 20426140 |
| 15 | 79079933 |
| 16 | 346099728 |
| 17 | 1365633469 |
| 18 | 6028191661 |
| 19 | 24148242373 |
| 20 | 107405519254 |
| 21 | 435530918701 |
| 22 | 1949357412248 |
| 23 | 7989116362455 |
| 24 | 35944021103058 |
| 25 | 148647982968273 |
| 26 | 671868249629145 |
| 27 | 2800152794320207 |
| 28 | 12706971263393744 |
[1,1,4,9,34,103,399,1329,5420,19005,79683,292567, 1246622,4721185,20426140,79079933,346099728, 1365633469,6028191661,24148242373,107405519254, 435530918701,1949357412248,7989116362455, 35944021103058,148647982968273,671868249629145, 2800152794320207,12706971263393744] |