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 | 20 |
| 2 | 270 |
| 3 | 3100 |
| 4 | 32711 |
| 5 | 328440 |
| 6 | 3195276 |
| 7 | 30433800 |
| 8 | 285604605 |
| 9 | 2651696300 |
| 10 | 24425110138 |
| 11 | 223636254660 |
| 12 | 2038173128355 |
| 13 | 18508562948400 |
| 14 | 167596683043032 |
| 15 | 1514149108652880 |
| 16 | 13654464563944377 |
| 17 | 122951462526317700 |
| 18 | 1105768912324277670 |
| 19 | 9934852156019798700 |
| 20 | 89186900539764803391 |