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 | 0 |
| 3 | 2 |
| 4 | 2 |
| 5 | 12 |
| 6 | 20 |
| 7 | 88 |
| 8 | 180 |
| 9 | 716 |
| 10 | 1648 |
| 11 | 6244 |
| 12 | 15512 |
| 13 | 57188 |
| 14 | 149892 |
| 15 | 543324 |
| 16 | 1481636 |
| 17 | 5310764 |
| 18 | 4930380 |
| 19 | 53102508 |
| 20 | 152935148 |
| 21 | 540918660 |
| 22 | 1588618212 |
| 23 | 5595773136 |
| 24 | 16701973552 |