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 | -2 |
| 2 | -12 |
| 3 | -40 |
| 4 | -112 |
| 5 | -288 |
| 6 | -704 |
| 7 | -1664 |
| 8 | -3840 |
| 9 | -8704 |
| 10 | -19456 |
| 11 | -43008 |
| 12 | -94208 |
| 13 | -204800 |
| 14 | -442368 |
| 15 | -950272 |
| 16 | -2031616 |
| 17 | -4325376 |
| 18 | -9175040 |
| 19 | -19398656 |
| 20 | -40894464 |
| 21 | -85983232 |
| 22 | -180355072 |
| 23 | -377487360 |
| 24 | -788529152 |
| 25 | -1644167168 |
| 26 | -3422552064 |
| 27 | -7113539584 |
| 28 | -14763950080 |