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 | 0 |
| 3 | 0 |
| 4 | 2 |
| 5 | 3 |
| 6 | 0 |
| 7 | 0 |
| 8 | 12 |
| 9 | 21 |
| 10 | 0 |
| 11 | 0 |
| 12 | 113 |
| 13 | 202 |
| 14 | 0 |
| 15 | 0 |
| 16 | 1218 |
| 17 | 2241 |
| 18 | 0 |
| 19 | 0 |
| 20 | 14326 |
| 21 | 26776 |
| 22 | 0 |
| 23 | 0 |
| 24 | 177714 |
| 25 | 335607 |
| 26 | 0 |
| 27 | 0 |
| 28 | 2287975 |
| 29 | 4353975 |
| 30 | 0 |
| 31 | 0 |
| 32 | 30282850 |
| 33 | 57965473 |
| 34 | 0 |
| 35 | 0 |
| 36 | 409476546 |
| 37 | 787414730 |
| 38 | 0 |
| 39 | 0 |
| 40 | 5631955466 |
| 41 | 10870618388 |
| 42 | 0 |
| 43 | 0 |
| 44 | 78545902971 |
| 45 | 152074824054 |
| 46 | 0 |
| 47 | 0 |