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) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 2 |
| 4 | -1 |
| 5 | 2 |
| 6 | 3 |
| 7 | -2 |
| 8 | 0 |
| 9 | 6 |
| 10 | 4 |
| 11 | -3 |
| 12 | -4 |
| 13 | 6 |
| 14 | 12 |
| 15 | 5 |
| 16 | -4 |
| 17 | -10 |
| 18 | 0 |
| 19 | 20 |
| 20 | 20 |
| 21 | 6 |
| 22 | -5 |
| 23 | -18 |
| 24 | -15 |
| 25 | 20 |
| 26 | 45 |
| 27 | 30 |
| 28 | 7 |
| 29 | -6 |
| 30 | -28 |
| 31 | -42 |
| 32 | 0 |
| 33 | 70 |
| 34 | 84 |
| 35 | 42 |
| 36 | 8 |
| 37 | -7 |
| 38 | -40 |
| 39 | -84 |
| 40 | -56 |
| 41 | 70 |
| 42 | 168 |
| 43 | 140 |
| 44 | 56 |
| 45 | 9 |
| 46 | -8 |
| 47 | -54 |
| 48 | -144 |
| 49 | -168 |
| 50 | 0 |
| 51 | 252 |
| 52 | 336 |
| 53 | 216 |
| 54 | 72 |
| 55 | 10 |