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 | 6 |
| 2 | 45 |
| 3 | 364 |
| 4 | 3060 |
| 5 | 26334 |
| 6 | 230230 |
| 7 | 2035800 |
| 8 | 18156204 |
| 9 | 163011640 |
| 10 | 1471442973 |
| 11 | 13340783196 |
| 12 | 121399651100 |
| 13 | 1108176102180 |
| 14 | 10142940735900 |
| 15 | 93052749919920 |
| 16 | 855420636763836 |
| 17 | 7877932561061640 |
| 18 | 72667580816130436 |
| 19 | 671262558647881200 |
| 20 | 6208770443303347920 |