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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 6 |
| 3 | 26 |
| 4 | 102 |
| 5 | 385 |
| 6 | 1430 |
| 7 | 5278 |
| 8 | 19448 |
| 9 | 71706 |
| 10 | 264860 |
| 11 | 980628 |
| 12 | 3640210 |
| 13 | 13549185 |
| 14 | 50565270 |
| 15 | 189194550 |
| 16 | 709634640 |
| 17 | 2667953310 |
| 18 | 10052743860 |
| 19 | 37957739820 |
| 20 | 143606349900 |
| 21 | 544321253658 |
| 22 | 2066802226236 |
| 23 | 7860697923436 |
| 24 | 29943415932752 |
| 25 | 114230459377300 |
| 26 | 436382974714232 |
[0,1,6,26,102,385,1430,5278,19448,71706,264860, 980628,3640210,13549185,50565270,189194550, 709634640,2667953310,10052743860,37957739820, 143606349900,544321253658,2066802226236, 7860697923436,29943415932752,114230459377300, 436382974714232] |