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 | 2 |
| 2 | 5 |
| 3 | 15 |
| 4 | 51 |
| 5 | 189 |
| 6 | 748 |
| 7 | 3128 |
| 8 | 13731 |
| 9 | 62969 |
| 10 | 300552 |
| 11 | 1488704 |
| 12 | 7634723 |
| 13 | 40464741 |
| 14 | 221311617 |
| 15 | 1247444859 |
| 16 | 7238458309 |
| 17 | 43196661875 |
| 18 | 264878725516 |
| 19 | 1667564565616 |
| 20 | 10770316016557 |
| 21 | 71314258947903 |
| 22 | 483765644021787 |
| 23 | 3359905164274725 |