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 | 1 |
| 1 | 0 |
| 2 | 8 |
| 3 | 4 |
| 4 | 48 |
| 5 | 68 |
| 6 | 284 |
| 7 | 684 |
| 8 | 1816 |
| 9 | 5608 |
| 10 | 12684 |
| 11 | 42068 |
| 12 | 92916 |
| 13 | 304100 |
| 14 | 688988 |
| 15 | 2170020 |
| 16 | 5088784 |
| 17 | 15436172 |
| 18 | 37281880 |
| 19 | 109786204 |
| 20 | 271062388 |
| 21 | 781016892 |
| 22 | 1958863988 |
| 23 | 5555714820 |
| 24 | 14090644980 |
| 25 | 39503105472 |
| 26 | 101000072900 |
| 27 | 280693435596 |