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 | 0 |
| 5 | 3 |
| 6 | 19 |
| 7 | 63 |
| 8 | 175 |
| 9 | 501 |
| 10 | 1230 |
| 11 | 3086 |
| 12 | 7469 |
| 13 | 18402 |
| 14 | 44748 |
| 15 | 109787 |
| 16 | 269289 |
| 17 | 668521 |
| 18 | 1675317 |
| 19 | 4236270 |