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 | 2 |
| 5 | 4 |
| 6 | 9 |
| 7 | 19 |
| 8 | 51 |
| 9 | 107 |
| 10 | 219 |
| 11 | 417 |
| 12 | 757 |
| 13 | 1470 |
| 14 | 2666 |
| 15 | 5040 |
| 16 | 9280 |
| 17 | 17210 |
| 18 | 32039 |
| 19 | 59762 |
| 20 | 111811 |
| 21 | 210627 |
| 22 | 397968 |