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 | 4 |
| 3 | 0 |
| 4 | 24 |
| 5 | 8 |
| 6 | 164 |
| 7 | 136 |
| 8 | 1236 |
| 9 | 1704 |
| 10 | 10116 |
| 11 | 19144 |
| 12 | 88616 |
| 13 | 205208 |
| 14 | 818764 |
| 15 | 2155160 |
| 16 | 7873440 |
| 17 | 22463400 |
| 18 | 77954740 |
| 19 | 233894600 |
| 20 | 788314984 |
| 21 | 2440865400 |
| 22 | 8095906076 |
| 23 | 25569342520 |
| 24 | 84107990356 |
| 25 | 269034666280 |