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 | -1 |
| 4 | 0 |
| 5 | -3 |
| 6 | 1 |
| 7 | 0 |
| 8 | -8 |
| 9 | 9 |
| 10 | -1 |
| 11 | 0 |
| 12 | -42 |
| 13 | 59 |
| 14 | -18 |
| 15 | 1 |
| 16 | 0 |
| 17 | -144 |
| 18 | 450 |
| 19 | -215 |
| 20 | 30 |
| 21 | -1 |
| 22 | 0 |
| 23 | -1440 |
| 24 | 3394 |
| 25 | -2475 |
| 26 | 565 |
| 27 | -45 |
| 28 | 1 |
| 29 | 0 |
| 30 | -5760 |
| 31 | 30912 |
| 32 | -28294 |
| 33 | 9345 |
| 34 | -1225 |
| 35 | 63 |
| 36 | -1 |
| 37 | 0 |
| 38 | -75600 |
| 39 | 293292 |
| 40 | -340116 |
| 41 | 147889 |
| 42 | -27720 |
| 43 | 2338 |
| 44 | -84 |
| 45 | 1 |
| 46 | 0 |
| 47 | -524160 |
| 48 | 3032208 |
| 49 | -4335596 |
| 50 | 2341332 |
| 51 | -579369 |
| 52 | 69552 |
| 53 | -4074 |
| 54 | 108 |
| 55 | -1 |
| 56 | 0 |
| 57 | -6531840 |