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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 8 |
| 3 | 22 |
| 4 | 61 |
| 5 | 174 |
| 6 | 504 |
| 7 | 1478 |
| 8 | 4374 |
| 9 | 13035 |
| 10 | 39062 |
| 11 | 117585 |
| 12 | 355279 |
| 13 | 1076845 |
| 14 | 3272692 |
| 15 | 9969385 |
| 16 | 30430982 |
| 17 | 93055869 |
| 18 | 285013326 |
| 19 | 874193006 |
| 20 | 2684778104 |
| 21 | 8254967674 |
| 22 | 25408703236 |
| 23 | 78283452265 |
| 24 | 241403160254 |
| 25 | 745024894092 |
| 26 | 2301051484006 |
| 27 | 7111897305089 |
| 28 | 21995136183906 |
[1,3,8,22,61,174,504,1478,4374,13035,39062,117585, 355279,1076845,3272692,9969385,30430982,93055869, 285013326,874193006,2684778104,8254967674, 25408703236,78283452265,241403160254,745024894092, 2301051484006,7111897305089,21995136183906] |