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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 19 |
| 5 | 69 |
| 6 | 259 |
| 7 | 995 |
| 8 | 3984 |
| 9 | 16246 |
| 10 | 67846 |
| 11 | 288622 |
| 12 | 1242949 |
| 13 | 5426505 |
| 14 | 23918477 |
| 15 | 106383490 |
| 16 | 477100523 |
| 17 | 2153840179 |
| 18 | 9786732365 |
| 19 | 44713258872 |
| 20 | 205300573048 |
| 21 | 946979887510 |
| 22 | 4385632308942 |
| 23 | 20387463346828 |
| 24 | 95097247477114 |
| 25 | 444963582043322 |
| 26 | 2088037680188809 |
| 27 | 9824186906449215 |
| 28 | 46336721367973800 |
[1,1,2,6,19,69,259,995,3984,16246,67846,288622, 1242949,5426505,23918477,106383490,477100523, 2153840179,9786732365,44713258872,205300573048, 946979887510,4385632308942,20387463346828, 95097247477114,444963582043322,2088037680188809, 9824186906449215,46336721367973800] |