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 | 2 |
| 2 | 12 |
| 3 | 54 |
| 4 | 206 |
| 5 | 712 |
| 6 | 2294 |
| 7 | 7024 |
| 8 | 20656 |
| 9 | 58842 |
| 10 | 163250 |
| 11 | 443062 |
| 12 | 1180156 |
| 13 | 3092964 |
| 14 | 7993116 |
| 15 | 20401250 |
| 16 | 51502616 |
| 17 | 128748512 |
| 18 | 319010540 |
| 19 | 784179992 |
| 20 | 1913668608 |
| 21 | 4639155964 |
| 22 | 11178566462 |
| 23 | 26784974870 |
| 24 | 63851541584 |