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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 10 |
| 7 | 28 |
| 8 | 127 |
| 9 | 686 |
| 10 | 4975 |
| 11 | 42529 |
| 12 | 420948 |
| 13 | 4622509 |
| 14 | 55670332 |
| 15 | 726738971 |
| 16 | 10217376792 |
| 17 | 153848448652 |
| 18 | 2470073249960 |
| 19 | 42120966152815 |
| 20 | 760282326662191 |
| 21 | 14481561464994821 |
| 22 | 290289454462745374 |
| 23 | 6108699653117045614 |
[1,1,1,2,4,10,28,127,686,4975,42529,420948, 4622509,55670332,726738971,10217376792, 153848448652,2470073249960,42120966152815, 760282326662191,14481561464994821, 290289454462745374,6108699653117045614] |