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 | 22 |
| 3 | 152 |
| 4 | 1161 |
| 5 | 9460 |
| 6 | 80550 |
| 7 | 708172 |
| 8 | 6379368 |
| 9 | 58576168 |
| 10 | 546215580 |
| 11 | 5158542152 |
| 12 | 49239812893 |
| 13 | 474285453628 |
| 14 | 4604149947276 |
| 15 | 44999181550032 |
| 16 | 442430807369519 |
| 17 | 4372944634271688 |
| 18 | 43425156714959956 |
| 19 | 433049078716727332 |
| 20 | 4334925824762251939 |