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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 2 |
| 5 | 10 |
| 6 | 44 |
| 7 | 179 |
| 8 | 702 |
| 9 | 2701 |
| 10 | 10278 |
| 11 | 38866 |
| 12 | 146450 |
| 13 | 550817 |
| 14 | 2070116 |
| 15 | 7779655 |
| 16 | 29248932 |
| 17 | 110047905 |
| 18 | 414446256 |
| 19 | 1562538171 |
| 20 | 5898049688 |
| 21 | 22290789562 |
| 22 | 84351810044 |
| 23 | 319609669957 |
| 24 | 1212552963576 |
| 25 | 4606078246284 |
| 26 | 17518748817596 |
| 27 | 66712192842068 |
| 28 | 254346235738120 |