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 | -18 |
| 2 | 0 |
| 3 | -90 |
| 4 | -234 |
| 5 | 0 |
| 6 | -216 |
| 7 | -900 |
| 8 | 0 |
| 9 | -738 |
| 10 | -1296 |
| 11 | 0 |
| 12 | -1170 |
| 13 | -3060 |
| 14 | 0 |
| 15 | -1728 |
| 16 | -3690 |
| 17 | 0 |
| 18 | -2160 |
| 19 | -6516 |
| 20 | 0 |
| 21 | -4500 |
| 22 | -6480 |
| 23 | 0 |
| 24 | -3672 |
| 25 | -10818 |
| 26 | 0 |
| 27 | -6570 |
| 28 | -11700 |
| 29 | 0 |
| 30 | -6480 |
| 31 | -17316 |
| 32 | 0 |
| 33 | -8640 |
| 34 | -15552 |
| 35 | 0 |
| 36 | -9594 |
| 37 | -24660 |
| 38 | 0 |
| 39 | -15300 |
| 40 | -22032 |
| 41 | 0 |
| 42 | -10800 |
| 43 | -33300 |
| 44 | 0 |
| 45 | -17280 |