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) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 0 |
| 5 | 4 |
| 6 | 17 |
| 7 | 55 |
| 8 | 161 |
| 9 | 449 |
| 10 | 1220 |
| 11 | 3266 |
| 12 | 8667 |
| 13 | 22879 |
| 14 | 60203 |
| 15 | 158107 |
| 16 | 414728 |
| 17 | 1087064 |
| 18 | 2848061 |
| 19 | 7459703 |
| 20 | 19535229 |
| 21 | 51152749 |
| 22 | 133933964 |
| 23 | 350666854 |
| 24 | 918095255 |
| 25 | 2403665279 |
| 26 | 6292975607 |
| 27 | 16475382935 |
| 28 | 43133369616 |
| 29 | 112925043724 |