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 | 0 |
| 2 | -1 |
| 3 | 0 |
| 4 | 1 |
| 5 | -3 |
| 6 | 0 |
| 7 | -2 |
| 8 | 5 |
| 9 | -11 |
| 10 | 0 |
| 11 | 6 |
| 12 | -9 |
| 13 | 49 |
| 14 | -25 |
| 15 | 0 |
| 16 | -24 |
| 17 | 51 |
| 18 | -251 |
| 19 | 205 |
| 20 | -137 |
| 21 | 0 |
| 22 | 120 |
| 23 | -99 |
| 24 | 1393 |
| 25 | -2035 |
| 26 | 5269 |
| 27 | -49 |
| 28 | 0 |
| 29 | -720 |
| 30 | 975 |
| 31 | -8051 |
| 32 | 22369 |
| 33 | -256103 |
| 34 | 5369 |
| 35 | -363 |
| 36 | 0 |
| 37 | 5040 |
| 38 | -5805 |
| 39 | 237245 |
| 40 | -257875 |
| 41 | 14001361 |
| 42 | -28567 |
| 43 | 266681 |
| 44 | -761 |
| 45 | 0 |
| 46 | -40320 |