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 | 1566 |
| 2 | 5430 |
| 3 | 18966 |
| 4 | 66294 |
| 5 | 231414 |
| 6 | 807630 |
| 7 | 2818830 |
| 8 | 9838974 |
| 9 | 34342350 |
| 10 | 119869158 |
| 11 | 418392870 |
| 12 | 1460364774 |
| 13 | 5097280614 |
| 14 | 17791629822 |
| 15 | 62100187038 |
| 16 | 216755476782 |
| 17 | 756566753022 |
| 18 | 2640732594966 |
| 19 | 9217254934326 |
| 20 | 32172052811478 |
| 21 | 112293843388758 |