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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 28 |
| 4 | 116 |
| 5 | 465 |
| 6 | 2002 |
| 7 | 8437 |
| 8 | 37237 |
| 9 | 161422 |
| 10 | 722872 |
| 11 | 3193287 |
| 12 | 14438915 |
| 13 | 64628012 |
| 14 | 294304218 |
| 15 | 1330034420 |
| 16 | 6090094043 |
| 17 | 27725305017 |
| 18 | 127515229293 |
| 19 | 583875027223 |
| 20 | 2695253214088 |
| 21 | 12398866699006 |
| 22 | 57412413236322 |
| 23 | 265130888541365 |
| 24 | 1230934711860059 |
| 25 | 5702885873267887 |
| 26 | 26537994068161571 |
| 27 | 123289342436536590 |
[1,2,8,28,116,465,2002,8437,37237,161422,722872, 3193287,14438915,64628012,294304218,1330034420, 6090094043,27725305017,127515229293,583875027223, 2695253214088,12398866699006,57412413236322, 265130888541365,1230934711860059,5702885873267887, 26537994068161571,123289342436536590] |