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 | 1 |
| 2 | 10 |
| 3 | 56 |
| 4 | 240 |
| 5 | 880 |
| 6 | 2912 |
| 7 | 8960 |
| 8 | 26112 |
| 9 | 72960 |
| 10 | 197120 |
| 11 | 518144 |
| 12 | 1331200 |
| 13 | 3354624 |
| 14 | 8314880 |
| 15 | 20316160 |
| 16 | 49020928 |
| 17 | 116981760 |
| 18 | 276430848 |
| 19 | 647495680 |
| 20 | 1504706560 |
| 21 | 3471835136 |
| 22 | 7958691840 |
| 23 | 18136170496 |
| 24 | 41104179200 |
| 25 | 92694118400 |
| 26 | 208071032832 |