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 | 1 |
| 3 | 4 |
| 4 | 13 |
| 5 | 38 |
| 6 | 105 |
| 7 | 280 |
| 8 | 737 |
| 9 | 1942 |
| 10 | 5183 |
| 11 | 14100 |
| 12 | 39151 |
| 13 | 110642 |
| 14 | 316751 |
| 15 | 914248 |
| 16 | 2650655 |
| 17 | 7701562 |
| 18 | 22400559 |
| 19 | 65203428 |
| 20 | 189970159 |
| 21 | 554165922 |
| 22 | 1619018259 |
| 23 | 4737859512 |
| 24 | 13887657307 |
| 25 | 40769959314 |
| 26 | 119849273449 |
| 27 | 352716050428 |
| 28 | 1039027117929 |