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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 7 |
| 3 | 20 |
| 4 | 55 |
| 5 | 148 |
| 6 | 403 |
| 7 | 1097 |
| 8 | 2981 |
| 9 | 8103 |
| 10 | 22026 |
| 11 | 59874 |
| 12 | 162755 |
| 13 | 442413 |
| 14 | 1202604 |
| 15 | 3269017 |
| 16 | 8886111 |
| 17 | 24154953 |
| 18 | 65659969 |
| 19 | 178482301 |
| 20 | 485165195 |
| 21 | 1318815734 |
| 22 | 3584912846 |
| 23 | 9744803446 |
| 24 | 26489122130 |
| 25 | 72004899337 |
| 26 | 195729609429 |
| 27 | 532048240602 |
| 28 | 1446257064291 |
| 29 | 3931334297144 |
| 30 | 10686474581524 |
[1,3,7,20,55,148,403,1097,2981,8103,22026,59874, 162755,442413,1202604,3269017,8886111,24154953, 65659969,178482301,485165195,1318815734, 3584912846,9744803446,26489122130,72004899337, 195729609429,532048240602,1446257064291, 3931334297144,10686474581524] |