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 | 4 |
| 2 | 20 |
| 3 | 84 |
| 4 | 356 |
| 5 | 1444 |
| 6 | 5876 |
| 7 | 23604 |
| 8 | 94852 |
| 9 | 379908 |
| 10 | 1521492 |
| 11 | 6088148 |
| 12 | 24360548 |
| 13 | 97451492 |
| 14 | 389838708 |
| 15 | 1559394356 |
| 16 | 6237711300 |
| 17 | 24951007620 |
| 18 | 99804576340 |
| 19 | 399218968084 |
| 20 | 1596878076132 |
| 21 | 6387515000292 |
| 22 | 25550068873908 |
| 23 | 102200286367156 |
| 24 | 408801181153476 |