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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 17 |
| 4 | 52 |
| 5 | 160 |
| 6 | 469 |
| 7 | 1337 |
| 8 | 3750 |
| 9 | 10347 |
| 10 | 28249 |
| 11 | 76382 |
| 12 | 204996 |
| 13 | 546651 |
| 14 | 1449952 |
| 15 | 3828232 |
| 16 | 10067585 |
| 17 | 26384939 |
| 18 | 68941126 |
| 19 | 179658343 |
| 20 | 467084601 |
| 21 | 1211812016 |
| 22 | 3138075544 |
| 23 | 8112667259 |
| 24 | 20941558268 |
| 25 | 53983767498 |
| 26 | 138989629481 |
| 27 | 357450757247 |
| 28 | 918350963486 |
| 29 | 2357213935865 |
| 30 | 6045360575469 |
[1,4,17,52,160,469,1337,3750,10347,28249,76382, 204996,546651,1449952,3828232,10067585,26384939, 68941126,179658343,467084601,1211812016, 3138075544,8112667259,20941558268,53983767498, 138989629481,357450757247,918350963486, 2357213935865,6045360575469] |