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 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 52 |
| 5 | 312 |
| 6 | 2290 |
| 7 | 19920 |
| 8 | 200522 |
| 9 | 2293677 |
| 10 | 29389005 |
| 11 | 416998371 |
| 12 | 6490825772 |
| 13 | 109972169413 |
| 14 | 2014696874717 |
| 15 | 39684502845893 |
| 16 | 836348775861331 |
| 17 | 18777970539419957 |
| 18 | 447471215460930665 |
| 19 | 11279275874429302811 |
| 20 | 299844572529989373703 |
| 21 | 8383794111721619471384 |
| 22 | 245956060268568277412668 |