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 | 7 |
| 5 | 23 |
| 6 | 66 |
| 7 | 187 |
| 8 | 485 |
| 9 | 1272 |
| 10 | 3270 |
| 11 | 8139 |
| 12 | 20015 |
| 13 | 50090 |
| 14 | 125284 |
| 15 | 318729 |
| 16 | 813380 |
| 17 | 2104139 |
| 18 | 5514763 |
| 19 | 14627441 |