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) |
|---|---|
| 3 | 1 |
| 4 | 4 |
| 5 | 16 |
| 6 | 56 |
| 7 | 197 |
| 8 | 694 |
| 9 | 2494 |
| 10 | 9244 |
| 11 | 35234 |
| 12 | 139228 |
| 13 | 566788 |
| 14 | 2387048 |
| 15 | 10343101 |
| 16 | 46193866 |
| 17 | 211775002 |
| 18 | 997265204 |
| 19 | 4809609062 |
| 20 | 23758479340 |
| 21 | 119952340180 |
| 22 | 618883933480 |
| 23 | 3257842530546 |
| 24 | 17492187873444 |
| 25 | 95680438560276 |
| 26 | 532985197799976 |
| 27 | 3020676725917252 |