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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 2 |
| 6 | 11 |
| 7 | 33 |
| 8 | 136 |
| 9 | 478 |
| 10 | 1849 |
| 11 | 6845 |
| 12 | 26136 |
| 13 | 98406 |
| 14 | 373977 |
| 15 | 1416249 |
| 16 | 5380770 |
| 17 | 20440250 |
| 18 | 77794939 |
| 19 | 296384565 |
| 20 | 1131009781 |
| 21 | 4321964735 |
| 22 | 16541268223 |
| 23 | 63400061153 |
| 24 | 243358777620 |
| 25 | 935431121460 |
| 26 | 3600520732809 |