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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 9 |
| 7 | 22 |
| 8 | 58 |
| 9 | 164 |
| 10 | 495 |
| 11 | 1587 |
| 12 | 5379 |
| 13 | 19195 |
| 14 | 71872 |
| 15 | 281571 |
| 16 | 1151338 |
| 17 | 4902687 |
| 18 | 21696505 |
| 19 | 99598840 |
| 20 | 473466698 |
| 21 | 2327173489 |
| 22 | 11810472444 |
| 23 | 61808852380 |
| 24 | 333170844940 |
| 25 | 1847741027555 |
| 26 | 10532499571707 |
| 27 | 61649191750137 |
| 28 | 370208647200165 |
| 29 | 2278936037262610 |
| 30 | 14369780182166215 |
[1,0,1,1,2,4,9,22,58,164,495,1587,5379,19195, 71872,281571,1151338,4902687,21696505,99598840, 473466698,2327173489,11810472444,61808852380, 333170844940,1847741027555,10532499571707, 61649191750137,370208647200165,2278936037262610, 14369780182166215] |