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 | -5 |
| 2 | 24 |
| 3 | -111 |
| 4 | 497 |
| 5 | -2166 |
| 6 | 9239 |
| 7 | -38765 |
| 8 | 160658 |
| 9 | -659773 |
| 10 | 2691205 |
| 11 | -10922544 |
| 12 | 44166173 |
| 13 | -178098121 |
| 14 | 716703848 |
| 15 | -2879774019 |
| 16 | 11558005677 |
| 17 | -46348854134 |
| 18 | 185746261419 |
| 19 | -744036460097 |
| 20 | 2979305960426 |
| 21 | -11926715433881 |
| 22 | 47735079979633 |
| 23 | -191026723545976 |
| 24 | 764362047956073 |
| 25 | -3058170811731677 |