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 | 0 |
| 5 | 1 |
| 6 | 1 |
| 7 | 6 |
| 8 | 11 |
| 9 | 42 |
| 10 | 92 |
| 11 | 294 |
| 12 | 720 |
| 13 | 2119 |
| 14 | 5460 |
| 15 | 15477 |
| 16 | 40989 |
| 17 | 114165 |
| 18 | 306980 |
| 19 | 848268 |
| 20 | 2301794 |
| 21 | 6341450 |
| 22 | 17308926 |
| 23 | 47659837 |
| 24 | 130628590 |
| 25 | 359924353 |
| 26 | 989642184 |
| 27 | 2730224431 |
| 28 | 7526539869 |
| 29 | 20795818601 |
| 30 | 57457010219 |