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 | 13 |
| 2 | 117 |
| 3 | 905 |
| 4 | 6461 |
| 5 | 43953 |
| 6 | 289717 |
| 7 | 1868425 |
| 8 | 11861421 |
| 9 | 74423393 |
| 10 | 462815717 |
| 11 | 2858273145 |
| 12 | 17556537181 |
| 13 | 107373722833 |
| 14 | 654414852117 |
| 15 | 3977351721065 |
| 16 | 24118423433741 |
| 17 | 145982106270273 |
| 18 | 882250466222917 |