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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 11 |
| 3 | 35 |
| 4 | 113 |
| 5 | 326 |
| 6 | 985 |
| 7 | 3124 |
| 8 | 8523 |
| 9 | 24519 |
| 10 | 71096 |
| 11 | 191940 |
| 12 | 530167 |
| 13 | 1442059 |
| 14 | 3833007 |
| 15 | 10243259 |
| 16 | 27151086 |
| 17 | 71032191 |
| 18 | 184492464 |
| 19 | 478339983 |
| 20 | 1227208513 |
| 21 | 3140958369 |
| 22 | 8016016201 |
| 23 | 20210235189 |
| 24 | 50962894061 |
| 25 | 127936646350 |
| 26 | 319022819270 |
| 27 | 794501931062 |
| 28 | 1969154638217 |
[1,4,11,35,113,326,985,3124,8523,24519,71096, 191940,530167,1442059,3833007,10243259,27151086, 71032191,184492464,478339983,1227208513, 3140958369,8016016201,20210235189,50962894061, 127936646350,319022819270,794501931062, 1969154638217] |