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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 15 |
| 4 | 67 |
| 5 | 265 |
| 6 | 1181 |
| 7 | 5035 |
| 8 | 22891 |
| 9 | 101385 |
| 10 | 467833 |
| 11 | 2124239 |
| 12 | 9908627 |
| 13 | 45726667 |
| 14 | 215107819 |
| 15 | 1004102949 |
| 16 | 4755098001 |
| 17 | 22389176879 |
| 18 | 106594259895 |
| 19 | 505286078225 |
| 20 | 2416188580561 |
| 21 | 11515108092133 |
| 22 | 55264506834405 |
| 23 | 264539724909511 |
| 24 | 1273537032925423 |
| 25 | 6118479896286207 |
| 26 | 29533597410434055 |
| 27 | 142327445758987571 |
[1,1,5,15,67,265,1181,5035,22891,101385,467833, 2124239,9908627,45726667,215107819,1004102949, 4755098001,22389176879,106594259895,505286078225, 2416188580561,11515108092133,55264506834405, 264539724909511,1273537032925423,6118479896286207, 29533597410434055,142327445758987571] |