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 | 12 |
| 2 | 90 |
| 3 | 520 |
| 4 | 2535 |
| 5 | 10908 |
| 6 | 42614 |
| 7 | 153960 |
| 8 | 521235 |
| 9 | 1669720 |
| 10 | 5098938 |
| 11 | 14931072 |
| 12 | 42124380 |
| 13 | 114945780 |
| 14 | 304351020 |
| 15 | 784087848 |
| 16 | 1970043621 |
| 17 | 4837060800 |
| 18 | 11626305640 |
| 19 | 27398234760 |
| 20 | 63388751544 |
| 21 | 144156086776 |
| 22 | 322590526350 |