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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 19 |
| 3 | 132 |
| 4 | 963 |
| 5 | 7228 |
| 6 | 55264 |
| 7 | 428067 |
| 8 | 3347843 |
| 9 | 26378079 |
| 10 | 209065644 |
| 11 | 1664967747 |
| 12 | 13312423056 |
| 13 | 106798422942 |
| 14 | 859244421187 |
| 15 | 6930167382832 |
| 16 | 56015610380931 |
| 17 | 453628706358333 |
| 18 | 3679805451367471 |
| 19 | 29895358350622638 |
| 20 | 243204082036270588 |
| 21 | 1980931117038586824 |
[1,3,19,132,963,7228,55264,428067,3347843, 26378079,209065644,1664967747,13312423056, 106798422942,859244421187,6930167382832, 56015610380931,453628706358333,3679805451367471, 29895358350622638,243204082036270588, 1980931117038586824] |