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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 17 |
| 6 | 52 |
| 7 | 144 |
| 8 | 480 |
| 9 | 1732 |
| 10 | 5902 |
| 11 | 21078 |
| 12 | 78434 |
| 13 | 289107 |
| 14 | 1079949 |
| 15 | 4094643 |
| 16 | 15574377 |
| 17 | 59667023 |
| 18 | 230318968 |
| 19 | 892694240 |
| 20 | 3477119540 |
| 21 | 13606993083 |
| 22 | 53438614380 |
| 23 | 210622413188 |
| 24 | 832922044686 |
| 25 | 3303392730698 |
| 26 | 13137474884294 |
| 27 | 52381331536536 |
| 28 | 209340904575968 |
[1,1,1,3,7,17,52,144,480,1732,5902,21078,78434, 289107,1079949,4094643,15574377,59667023, 230318968,892694240,3477119540,13606993083, 53438614380,210622413188,832922044686, 3303392730698,13137474884294,52381331536536, 209340904575968] |