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 | 6 |
| 3 | 26 |
| 4 | 91 |
| 5 | 414 |
| 6 | 1519 |
| 7 | 6980 |
| 8 | 26176 |
| 9 | 120596 |
| 10 | 457880 |
| 11 | 2110422 |
| 12 | 8076044 |
| 13 | 37211408 |
| 14 | 143165518 |
| 15 | 659264978 |
| 16 | 2546261659 |
| 17 | 11717539646 |
| 18 | 45387607779 |
| 19 | 208729977124 |
| 20 | 810316893827 |