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 | 3 |
| 3 | 2 |
| 4 | 4 |
| 5 | 11 |
| 6 | -13 |
| 7 | 36 |
| 8 | 56 |
| 9 | -515 |
| 10 | 2067 |
| 11 | -3890 |
| 12 | -9620 |
| 13 | 129047 |
| 14 | -664349 |
| 15 | 1837920 |
| 16 | 2388704 |
| 17 | -67004679 |
| 18 | 478198563 |
| 19 | -1994889926 |
| 20 | 1669470804 |
| 21 | 56929813955 |
| 22 | -615188040173 |
| 23 | 3794477505596 |
| 24 | -12028579019512 |
| 25 | -50780206473195 |
| 26 | 1172949397924211 |
| 27 | -10766410530764090 |