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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 19 |
| 5 | 63 |
| 6 | 216 |
| 7 | 760 |
| 8 | 2725 |
| 9 | 9910 |
| 10 | 36446 |
| 11 | 135268 |
| 12 | 505861 |
| 13 | 1903890 |
| 14 | 7204874 |
| 15 | 27394666 |
| 16 | 104592937 |
| 17 | 400795844 |
| 18 | 1540820542 |
| 19 | 5940738676 |
| 20 | 22964779660 |
| 21 | 88983512783 |
| 22 | 345532572678 |
| 23 | 1344372335524 |
| 24 | 5239988770268 |
| 25 | 20457802016011 |
| 26 | 79992676367108 |
| 27 | 313224032098244 |
| 28 | 1228088671826973 |