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 | 1 |
| 2 | 9 |
| 3 | 45 |
| 4 | 173 |
| 5 | 573 |
| 6 | 1725 |
| 7 | 4861 |
| 8 | 13053 |
| 9 | 33789 |
| 10 | 84989 |
| 11 | 208893 |
| 12 | 503805 |
| 13 | 1196029 |
| 14 | 2801661 |
| 15 | 6488061 |
| 16 | 14876669 |
| 17 | 33816573 |
| 18 | 76283901 |
| 19 | 170917885 |
| 20 | 380633085 |
| 21 | 843055101 |
| 22 | 1858076669 |
| 23 | 4076863485 |
| 24 | 8908701693 |
| 25 | 19394461693 |
| 26 | 42077257725 |
| 27 | 90999619581 |
| 28 | 196226318333 |