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 | 3 |
| 2 | 9 |
| 3 | 30 |
| 4 | 105 |
| 5 | 378 |
| 6 | 1386 |
| 7 | 5148 |
| 8 | 19305 |
| 9 | 72930 |
| 10 | 277134 |
| 11 | 1058148 |
| 12 | 4056234 |
| 13 | 15600900 |
| 14 | 60174900 |
| 15 | 232676280 |
| 16 | 901620585 |
| 17 | 3500409330 |
| 18 | 13612702950 |
| 19 | 53017895700 |
| 20 | 206769793230 |
| 21 | 807386811660 |
| 22 | 3156148445580 |
| 23 | 12350146091400 |
| 24 | 48371405524650 |