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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 12 |
| 5 | 36 |
| 6 | 114 |
| 7 | 375 |
| 8 | 1071 |
| 9 | 2939 |
| 10 | 7706 |
| 11 | 20417 |
| 12 | 53332 |
| 13 | 139597 |
| 14 | 364217 |
| 15 | 957111 |
| 16 | 2526795 |
| 17 | 6725234 |
| 18 | 18069359 |
| 19 | 48961462 |