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 | 2 |
| 2 | 3 |
| 3 | 6 |
| 4 | 17 |
| 5 | 54 |
| 6 | 153 |
| 7 | 552 |
| 8 | 2057 |
| 9 | 8394 |
| 10 | 35539 |
| 11 | 166926 |
| 12 | 856189 |
| 13 | 4674890 |
| 14 | 27358553 |
| 15 | 171129072 |
| 16 | 1141190303 |
| 17 | 8017021932 |
| 18 | 59365844491 |
| 19 | 461939618824 |