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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 22 |
| 4 | 86 |
| 5 | 316 |
| 6 | 1314 |
| 7 | 5236 |
| 8 | 22608 |
| 9 | 94591 |
| 10 | 418720 |
| 11 | 1809437 |
| 12 | 8152191 |
| 13 | 36042798 |
| 14 | 164532212 |
| 15 | 739869381 |
| 16 | 3411910087 |
| 17 | 15543863248 |
| 18 | 72262806914 |
| 19 | 332620036343 |
| 20 | 1556574199804 |
| 21 | 7224695770488 |
| 22 | 33995656854255 |
| 23 | 158873726063244 |
| 24 | 751049396267312 |
| 25 | 3530122036974346 |
| 26 | 16754410594433543 |
| 27 | 79134147930815117 |
[1,2,7,22,86,316,1314,5236,22608,94591,418720, 1809437,8152191,36042798,164532212,739869381, 3411910087,15543863248,72262806914,332620036343, 1556574199804,7224695770488,33995656854255, 158873726063244,751049396267312,3530122036974346, 16754410594433543,79134147930815117] |