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 | 0 |
| 4 | 3 |
| 5 | 13 |
| 6 | 40 |
| 7 | 194 |
| 8 | 389 |
| 9 | 1407 |
| 10 | 3646 |
| 11 | 13300 |
| 12 | 39166 |
| 13 | 131464 |
| 14 | 389575 |
| 15 | 1627565 |
| 16 | 5556317 |
| 17 | 19913811 |
| 18 | 72249861 |
| 19 | 272188855 |
| 20 | 996509475 |