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) |
|---|---|
| 4 | 1 |
| 5 | 10 |
| 6 | 57 |
| 7 | 245 |
| 8 | 888 |
| 9 | 2881 |
| 10 | 8679 |
| 11 | 24872 |
| 12 | 68940 |
| 13 | 186953 |
| 14 | 499927 |
| 15 | 1325204 |
| 16 | 3494249 |
| 17 | 9184675 |
| 18 | 24098536 |
| 19 | 63165197 |
| 20 | 165471668 |
| 21 | 433350754 |
| 22 | 1134715190 |
| 23 | 2970971916 |
| 24 | 7778430788 |
| 25 | 20364616458 |
| 26 | 53315795326 |
| 27 | 139583244540 |