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 | 4 |
| 2 | 12 |
| 3 | 41 |
| 4 | 156 |
| 5 | 624 |
| 6 | 2604 |
| 7 | 11160 |
| 8 | 48828 |
| 9 | 217013 |
| 10 | 976562 |
| 11 | 4438920 |
| 12 | 20345052 |
| 13 | 93900240 |
| 14 | 435965401 |
| 15 | 2034505208 |
| 16 | 9536743164 |
| 17 | 44878791360 |
| 18 | 211927625868 |
| 19 | 1003867701480 |
| 20 | 4768371582031 |
| 21 | 22706531343005 |
| 22 | 108372081409801 |
| 23 | 518301258916440 |
| 24 | 2483526865641276 |