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 | 18 |
| 3 | 189 |
| 4 | 2106 |
| 5 | 22113 |
| 6 | 220158 |
| 7 | 2114829 |
| 8 | 19853586 |
| 9 | 183662073 |
| 10 | 1683014598 |
| 11 | 15327998469 |
| 12 | 139038783066 |
| 13 | 1257874611633 |
| 14 | 11360039237838 |
| 15 | 102475402586109 |
| 16 | 923689049088546 |
| 17 | 8321664384098793 |
| 18 | 74945758272961878 |
| 19 | 674816500839877749 |