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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 9 |
| 4 | 21 |
| 5 | 49 |
| 6 | 114 |
| 7 | 266 |
| 8 | 620 |
| 9 | 1446 |
| 10 | 3372 |
| 11 | 7864 |
| 12 | 18340 |
| 13 | 42772 |
| 14 | 99752 |
| 15 | 232640 |
| 16 | 542560 |
| 17 | 1265352 |
| 18 | 2951040 |
| 19 | 6882384 |
| 20 | 16051024 |
| 21 | 37434032 |
| 22 | 87303264 |
| 23 | 203607776 |
| 24 | 474851968 |
| 25 | 1107444896 |
| 26 | 2582771648 |
| 27 | 6023513600 |
| 28 | 14047976768 |
| 29 | 32762547648 |
| 30 | 76408478336 |
[1,4,9,21,49,114,266,620,1446,3372,7864,18340, 42772,99752,232640,542560,1265352,2951040,6882384, 16051024,37434032,87303264,203607776,474851968, 1107444896,2582771648,6023513600,14047976768, 32762547648,76408478336] |