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 | 1 |
| 1 | 1 |
| 2 | -3 |
| 3 | -11 |
| 4 | 25 |
| 5 | 201 |
| 6 | -299 |
| 7 | -5123 |
| 8 | 3249 |
| 9 | 167185 |
| 10 | 50221 |
| 11 | -6637179 |
| 12 | -8846903 |
| 13 | 309737689 |
| 14 | 769776645 |
| 15 | -16575533939 |
| 16 | -62762132639 |
| 17 | 998072039457 |
| 18 | 5265897058909 |
| 19 | -66595289781995 |
| 20 | -466803466259079 |
| 21 | 4860819716300521 |
| 22 | 44072310882063157 |
| 23 | -383679824152382691 |