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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 22 |
| 4 | 91 |
| 5 | 383 |
| 6 | 1668 |
| 7 | 7411 |
| 8 | 33476 |
| 9 | 152897 |
| 10 | 707145 |
| 11 | 3299234 |
| 12 | 15490659 |
| 13 | 73143589 |
| 14 | 347167321 |
| 15 | 1654542464 |
| 16 | 7912965246 |
| 17 | 37970582001 |
| 18 | 182724292495 |
| 19 | 881421183634 |
| 20 | 4261082344830 |
| 21 | 20641085036137 |
| 22 | 100163243902972 |
| 23 | 486821506316846 |
| 24 | 2369576128859998 |
| 25 | 11549163118691787 |
| 26 | 56357043289847950 |
| 27 | 275312066835176586 |
[1,2,6,22,91,383,1668,7411,33476,152897,707145, 3299234,15490659,73143589,347167321,1654542464, 7912965246,37970582001,182724292495,881421183634, 4261082344830,20641085036137,100163243902972, 486821506316846,2369576128859998, 11549163118691787,56357043289847950, 275312066835176586] |