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 | 9 |
| 5 | 24 |
| 6 | 57 |
| 7 | 140 |
| 8 | 376 |
| 9 | 1016 |
| 10 | 2692 |
| 11 | 7020 |
| 12 | 18369 |
| 13 | 48344 |
| 14 | 127465 |
| 15 | 335510 |
| 16 | 882081 |
| 17 | 2319136 |
| 18 | 6100393 |
| 19 | 16049440 |
| 20 | 42220168 |
| 21 | 111053856 |
| 22 | 292109320 |
| 23 | 768373144 |
| 24 | 2021186393 |
| 25 | 5316647448 |
| 26 | 13985104873 |
| 27 | 36786882378 |
| 28 | 96765680857 |
| 29 | 254536684328 |