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) |
|---|---|
| 2 | 2 |
| 3 | 4 |
| 4 | 25 |
| 5 | 181 |
| 6 | 421 |
| 7 | 3930 |
| 8 | 8177 |
| 9 | 102772 |
| 10 | 199981 |
| 11 | 3179142 |
| 12 | 5971945 |
| 13 | 143610511 |
| 14 | 210826981 |
| 15 | 4754446846 |
| 16 | 8589934561 |
| 17 | 222195898593 |
| 18 | 396718580701 |
| 19 | 13494919482970 |
| 20 | 20479999999961 |
| 21 | 764527028941797 |
| 22 | 1168636602822613 |
| 23 | 41826814261329722 |
| 24 | 73040694872113105 |
| 25 | 2855533828630999398 |