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 | 4 |
| 3 | 18 |
| 4 | 73 |
| 5 | 334 |
| 6 | 2592 |
| 7 | 18919 |
| 8 | 164476 |
| 9 | 1558521 |
| 10 | 1 |
| 11 | 187044031 |
| 12 | 2326111614 |
| 13 | 31214008090 |