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 | -1 |
| 3 | 1 |
| 4 | 0 |
| 5 | -3 |
| 6 | 5 |
| 7 | 9 |
| 8 | -44 |
| 9 | -50 |
| 10 | 545 |
| 11 | 572 |
| 12 | -9890 |
| 13 | -13263 |
| 14 | 251236 |
| 15 | 490208 |
| 16 | -8309897 |
| 17 | -25084529 |
| 18 | 340735734 |
| 19 | 1618199204 |
| 20 | -16683530000 |
| 21 | -123071639020 |
| 22 | 922641297931 |
| 23 | 10768715419165 |
| 24 | -53177799474462 |
| 25 | -1066100082041498 |