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) |
|---|---|
| 1 | 1 |
| 2 | 133 |
| 3 | 2842 |
| 4 | 29274 |
| 5 | 197400 |
| 6 | 1001952 |
| 7 | 4137966 |
| 8 | 14597934 |
| 9 | 45454773 |
| 10 | 127861825 |
| 11 | 330540028 |
| 12 | 795609724 |
| 13 | 1801339176 |
| 14 | 3867558072 |
| 15 | 7926516900 |
| 16 | 15591322404 |
| 17 | 29566276257 |
| 18 | 54259095093 |
| 19 | 96674782246 |
| 20 | 167695627750 |
| 21 | 283882296880 |