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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 9 |
| 4 | 28 |
| 5 | 126 |
| 6 | 585 |
| 7 | 2198 |
| 8 | 9632 |
| 9 | 44226 |
| 10 | 167832 |
| 11 | 704970 |
| 12 | 3543517 |
| 13 | 12649338 |
| 14 | 53609220 |
| 15 | 257397588 |
| 16 | 1000032768 |
| 17 | 4073003174 |
| 18 | 19720373400 |
| 19 | 73088555292 |
| 20 | 323884878912 |
| 21 | 1476102415284 |
| 22 | 5555586582000 |
| 23 | 23533806109394 |