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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 9 |
| 4 | 19 |
| 5 | 42 |
| 6 | 93 |
| 7 | 205 |
| 8 | 452 |
| 9 | 997 |
| 10 | 2199 |
| 11 | 4850 |
| 12 | 10697 |
| 13 | 23593 |
| 14 | 52036 |
| 15 | 114769 |
| 16 | 253131 |
| 17 | 558298 |
| 18 | 1231365 |
| 19 | 2715861 |
| 20 | 5990020 |
| 21 | 13211405 |
| 22 | 29138671 |
| 23 | 64267362 |
| 24 | 141746129 |
| 25 | 312630929 |
| 26 | 689529220 |
| 27 | 1520804569 |
| 28 | 3354240067 |
| 29 | 7398009354 |
| 30 | 16316823277 |
[1,4,9,19,42,93,205,452,997,2199,4850,10697,23593, 52036,114769,253131,558298,1231365,2715861, 5990020,13211405,29138671,64267362,141746129, 312630929,689529220,1520804569,3354240067, 7398009354,16316823277] |