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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 14 |
| 5 | 52 |
| 6 | 195 |
| 7 | 774 |
| 8 | 3140 |
| 9 | 13118 |
| 10 | 55861 |
| 11 | 241988 |
| 12 | 1062411 |
| 13 | 4718380 |
| 14 | 21156811 |
| 15 | 95652842 |
| 16 | 435553638 |
| 17 | 1995707806 |
| 18 | 9194770161 |
| 19 | 42570402238 |
| 20 | 197957907525 |
| 21 | 924157498638 |
| 22 | 4329762257151 |
| 23 | 20351029400480 |
| 24 | 95938011359954 |
| 25 | 453492517932696 |
| 26 | 2148971058064469 |
| 27 | 10206782449568402 |
| 28 | 48581518322215785 |
[1,1,4,14,52,195,774,3140,13118,55861,241988, 1062411,4718380,21156811,95652842,435553638, 1995707806,9194770161,42570402238,197957907525, 924157498638,4329762257151,20351029400480, 95938011359954,453492517932696,2148971058064469, 10206782449568402,48581518322215785] |