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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 4 |
| 5 | 8 |
| 6 | 29 |
| 7 | 79 |
| 8 | 280 |
| 9 | 912 |
| 10 | 3260 |
| 11 | 11410 |
| 12 | 41272 |
| 13 | 148976 |
| 14 | 544802 |
| 15 | 1997499 |
| 16 | 7372080 |
| 17 | 27299360 |
| 18 | 101520714 |
| 19 | 378721134 |
| 20 | 1417339352 |
| 21 | 5318837680 |
| 22 | 20012141478 |
| 23 | 75473438326 |
| 24 | 285268537424 |
| 25 | 1080433781728 |
| 26 | 4099860518208 |
| 27 | 15585111068644 |
| 28 | 59343308199216 |
| 29 | 226312777319776 |
[0,1,1,4,8,29,79,280,912,3260,11410,41272,148976, 544802,1997499,7372080,27299360,101520714, 378721134,1417339352,5318837680,20012141478, 75473438326,285268537424,1080433781728, 4099860518208,15585111068644,59343308199216, 226312777319776] |