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 | 4 |
| 3 | 12 |
| 4 | 152 |
| 5 | 424 |
| 6 | 5180 |
| 7 | 14420 |
| 8 | 175984 |
| 9 | 489872 |
| 10 | 5978292 |
| 11 | 16641244 |
| 12 | 203085960 |
| 13 | 565312440 |
| 14 | 6898944364 |
| 15 | 19203981732 |
| 16 | 234361022432 |
| 17 | 652370066464 |
| 18 | 7961375818340 |
| 19 | 22161378278060 |
| 20 | 270452416801144 |
| 21 | 752834491387592 |
| 22 | 9187420795420572 |
| 23 | 25574211328900084 |