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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 0 |
| 5 | 3 |
| 6 | 0 |
| 7 | 14 |
| 8 | 0 |
| 9 | 15 |
| 10 | 28 |
| 11 | 0 |
| 12 | 132 |
| 13 | 0 |
| 14 | 105 |
| 15 | 0 |
| 16 | 5556 |
| 17 | 0 |
| 18 | 1500 |
| 19 | 0 |
| 20 | 945 |
| 21 | 1112 |
| 22 | 0 |
| 23 | 10668 |
| 24 | 0 |
| 25 | 1995 |
| 26 | 0 |
| 27 | 10395 |
| 28 | 0 |
| 29 | 43784 |
| 30 | 0 |
| 31 | 212940 |
| 32 | 0 |
| 33 | 304290 |
| 34 | 0 |
| 35 | 135135 |
| 36 | 87568 |
| 37 | 0 |
| 38 | 1408992 |
| 39 | 0 |
| 40 | 4533480 |
| 41 | 0 |
| 42 | 5239080 |
| 43 | 0 |
| 44 | 2027025 |