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 | 2 |
| 3 | 2 |
| 4 | 8 |
| 5 | 16 |
| 6 | 46 |
| 7 | 114 |
| 8 | 310 |
| 9 | 822 |
| 10 | 2238 |
| 11 | 6094 |
| 12 | 16764 |
| 13 | 46308 |
| 14 | 128650 |
| 15 | 358862 |
| 16 | 1005056 |
| 17 | 2824416 |
| 18 | 7962122 |
| 19 | 22508350 |
| 20 | 63792424 |
| 21 | 181219680 |
| 22 | 515905018 |
| 23 | 1471593638 |
| 24 | 4205280902 |
| 25 | 12037415526 |
| 26 | 34510499066 |
| 27 | 99083855234 |
| 28 | 284870069780 |