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 | 4 |
| 2 | 23 |
| 3 | 176 |
| 4 | 1689 |
| 5 | 19524 |
| 6 | 264207 |
| 7 | 4098240 |
| 8 | 71697105 |
| 9 | 1396704420 |
| 10 | 29985521895 |
| 11 | 703416314160 |
| 12 | 17901641997225 |
| 13 | 491250187505700 |
| 14 | 14459713484342175 |
| 15 | 454441401368236800 |
| 16 | 15188465029114325025 |
| 17 | 537928935889764226500 |