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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 9 |
| 3 | 25 |
| 4 | 56 |
| 5 | 143 |
| 6 | 273 |
| 7 | 578 |
| 8 | 1045 |
| 9 | 2047 |
| 10 | 4176 |
| 11 | 7223 |
| 12 | 13949 |
| 13 | 25010 |
| 14 | 42441 |
| 15 | 75059 |
| 16 | 136952 |
| 17 | 246679 |
| 18 | 412665 |
| 19 | 733382 |
| 20 | 1257481 |
| 21 | 2091961 |
| 22 | 3663072 |
| 23 | 6227075 |
| 24 | 10803977 |
| 25 | 19052546 |
| 26 | 32098911 |
| 27 | 52965587 |
| 28 | 89028280 |
| 29 | 146743321 |
| 30 | 246148917 |
| 31 | 447621406 |
[4,9,25,56,143,273,578,1045,2047,4176,7223,13949, 25010,42441,75059,136952,246679,412665,733382, 1257481,2091961,3663072,6227075,10803977,19052546, 32098911,52965587,89028280,146743321,246148917, 447621406] |