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 | 5 |
| 4 | 19 |
| 5 | 73 |
| 6 | 292 |
| 7 | 1203 |
| 8 | 5065 |
| 9 | 21697 |
| 10 | 94274 |
| 11 | 414514 |
| 12 | 1840981 |
| 13 | 8247011 |
| 14 | 37220261 |
| 15 | 169079113 |
| 16 | 772489020 |
| 17 | 3547371679 |
| 18 | 16364309243 |
| 19 | 75799327800 |
| 20 | 352402156770 |
| 21 | 1643878188646 |
| 22 | 7691841654538 |
| 23 | 36091803172733 |