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 | 6 |
| 3 | 29 |
| 4 | 209 |
| 5 | 1652 |
| 6 | 15981 |
| 7 | 171837 |
| 8 | 2060481 |
| 9 | 26951143 |
| 10 | 381398614 |
| 11 | 5789262973 |
| 12 | 93674732887 |
| 13 | 1607249998772 |
| 14 | 29114205685585 |
| 15 | 554699253112833 |
| 16 | 11079840198856480 |
| 17 | 231366880421810416 |
| 18 | 5038182952520057443 |
| 19 | 114152394913959017721 |
| 20 | 2685768694808159100283 |