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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 11 |
| 4 | 55 |
| 5 | 167 |
| 6 | 835 |
| 7 | 2857 |
| 8 | 14285 |
| 9 | 52561 |
| 10 | 262805 |
| 11 | 1013105 |
| 12 | 5065525 |
| 13 | 20180161 |
| 14 | 100900805 |
| 15 | 411873731 |
| 16 | 2059368655 |
| 17 | 8565364651 |
| 18 | 42826823255 |
| 19 | 180795858315 |
| 20 | 903979291575 |
| 21 | 3862606377623 |
| 22 | 19313031888115 |
| 23 | 83352807019527 |
| 24 | 416764035097635 |
| 25 | 1813923288348959 |
| 26 | 9069616441744795 |
| 27 | 39759273865609487 |
[1,1,5,11,55,167,835,2857,14285,52561,262805, 1013105,5065525,20180161,100900805,411873731, 2059368655,8565364651,42826823255,180795858315, 903979291575,3862606377623,19313031888115, 83352807019527,416764035097635,1813923288348959, 9069616441744795,39759273865609487] |