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 | 0 |
| 1 | 1 |
| 2 | 0 |
| 3 | -1 |
| 4 | 4 |
| 5 | 0 |
| 6 | 4 |
| 7 | -9 |
| 8 | 9 |
| 9 | 0 |
| 10 | -33 |
| 11 | 64 |
| 12 | -36 |
| 13 | 16 |
| 14 | 0 |
| 15 | 456 |
| 16 | -825 |
| 17 | 400 |
| 18 | -100 |
| 19 | 25 |
| 20 | 0 |
| 21 | -9460 |
| 22 | 16416 |
| 23 | -7425 |
| 24 | 1600 |
| 25 | -225 |
| 26 | 36 |
| 27 | 0 |
| 28 | 274800 |
| 29 | -463540 |
| 30 | 201096 |
| 31 | -40425 |
| 32 | 4900 |
| 33 | -441 |
| 34 | 49 |
| 35 | 0 |
| 36 | -10643745 |
| 37 | 17587200 |
| 38 | -7416640 |
| 39 | 1430016 |
| 40 | -161700 |
| 41 | 12544 |
| 42 | -784 |
| 43 | 64 |
| 44 | 0 |
| 45 | 530052880 |
| 46 | -862143345 |
| 47 | 356140800 |
| 48 | -66749760 |
| 49 | 7239456 |