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 | 0 |
| 2 | -1 |
| 3 | -1 |
| 4 | -2 |
| 5 | -6 |
| 6 | -14 |
| 7 | -27 |
| 8 | -39 |
| 9 | -4 |
| 10 | 269 |
| 11 | 1415 |
| 12 | 5258 |
| 13 | 16321 |
| 14 | 43705 |
| 15 | 98459 |
| 16 | 163216 |
| 17 | 49326 |
| 18 | -1120684 |
| 19 | -6502098 |
| 20 | -25711856 |
| 21 | -83830889 |
| 22 | -233926105 |
| 23 | -545916369 |
| 24 | -932372648 |
| 25 | -280663557 |
| 26 | 6802456973 |
| 27 | 40262637059 |
| 28 | 162298734532 |
| 29 | 538385811978 |