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 | 16 |
| 5 | 32 |
| 6 | 76 |
| 7 | 384 |
| 8 | 386 |
| 9 | 2976 |
| 10 | 3952 |
| 11 | 20520 |
| 12 | 41104 |
| 13 | 136160 |
| 14 | 393624 |
| 15 | 1027072 |
| 16 | 3412146 |
| 17 | 8470840 |
| 18 | 27988904 |
| 19 | 74155272 |
| 20 | 230939032 |
| 21 | 655493408 |
| 22 | 1942645984 |
| 23 | 5765577688 |
| 24 | 16807041186 |
| 25 | 50708538824 |
| 26 | 148118970352 |
| 27 | 446903215688 |
| 28 | 1320213337712 |
| 29 | 3968685090000 |