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 | 12 |
| 4 | 57 |
| 5 | 312 |
| 6 | 1950 |
| 7 | 13848 |
| 8 | 111069 |
| 9 | 998064 |
| 10 | 9957186 |
| 11 | 109305240 |
| 12 | 1309637274 |
| 13 | 17006109072 |
| 14 | 237888664572 |
| 15 | 3566114897520 |
| 16 | 57030565449765 |
| 17 | 969154436550240 |
| 18 | 17439499379433690 |
| 19 | 331268545604793240 |
| 20 | 6624013560942038670 |
| 21 | 139080391965533653200 |
| 22 | 3059323407592802838180 |
| 23 | 70355685298375014175440 |