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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 18 |
| 5 | 47 |
| 6 | 141 |
| 7 | 432 |
| 8 | 1329 |
| 9 | 4452 |
| 10 | 14295 |
| 11 | 49817 |
| 12 | 167179 |
| 13 | 591475 |
| 14 | 2062501 |
| 15 | 7357786 |
| 16 | 26446105 |
| 17 | 95239479 |
| 18 | 349688079 |
| 19 | 1274422929 |
| 20 | 4742103229 |
| 21 | 17511528513 |
| 22 | 65687166495 |
| 23 | 245724681207 |
| 24 | 926977717315 |
| 25 | 3507504480858 |
| 26 | 13301679890417 |
| 27 | 50792123226168 |
| 28 | 193720256273361 |
| 29 | 744703358194793 |
| 30 | 2857772882473509 |
[1,1,3,6,18,47,141,432,1329,4452,14295,49817, 167179,591475,2062501,7357786,26446105,95239479, 349688079,1274422929,4742103229,17511528513, 65687166495,245724681207,926977717315, 3507504480858,13301679890417,50792123226168, 193720256273361,744703358194793,2857772882473509] |