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 | 21 |
| 2 | 273 |
| 3 | 2716 |
| 4 | 22659 |
| 5 | 165984 |
| 6 | 1098615 |
| 7 | 6695559 |
| 8 | 38085117 |
| 9 | 204218630 |
| 10 | 1040291595 |
| 11 | 5064987207 |
| 12 | 23686610269 |
| 13 | 106828575357 |
| 14 | 466231753944 |
| 15 | 1974651627802 |
| 16 | 8136148603086 |
| 17 | 32681975601387 |
| 18 | 128221943065839 |