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 | 0 |
| 2 | 6 |
| 3 | 6 |
| 4 | 66 |
| 5 | 156 |
| 6 | 966 |
| 7 | 3366 |
| 8 | 16986 |
| 9 | 70386 |
| 10 | 332646 |
| 11 | 1484676 |
| 12 | 6922146 |
| 13 | 31921506 |
| 14 | 149341506 |
| 15 | 700002366 |
| 16 | 3299514906 |
| 17 | 15618721956 |
| 18 | 74169285366 |