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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 3 |
| 5 | 8 |
| 6 | 20 |
| 7 | 51 |
| 8 | 121 |
| 9 | 276 |
| 10 | 612 |
| 11 | 1335 |
| 12 | 2881 |
| 13 | 6144 |
| 14 | 12950 |
| 15 | 27029 |
| 16 | 55977 |
| 17 | 115222 |
| 18 | 236058 |
| 19 | 481683 |
| 20 | 979443 |