This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 17 |
| 3 | 91 |
| 4 | 449 |
| 5 | 2123 |
| 6 | 9841 |
| 7 | 45211 |
| 8 | 206881 |
| 9 | 945003 |
| 10 | 4313297 |
| 11 | 19680571 |
| 12 | 89784449 |
| 13 | 409577483 |
| 14 | 1868351281 |
| 15 | 8522666971 |
| 16 | 38876763361 |
| 17 | 177338745003 |
| 18 | 808940722577 |
| 19 | 3690027171451 |
| 20 | 16832256509249 |
| 21 | 76781232397643 |
| 22 | 350241657358321 |
| 23 | 1597645838773531 |
| 24 | 7287745912705441 |