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 | 2 |
| 2 | -10 |
| 3 | 86 |
| 4 | -902 |
| 5 | 10506 |
| 6 | -130594 |
| 7 | 1697006 |
| 8 | -22774094 |
| 9 | 313205522 |
| 10 | -4391039930 |
| 11 | 62522730310 |
| 12 | -901680559574 |
| 13 | 13143551082138 |
| 14 | -193339856081490 |
| 15 | 2866341942620382 |
| 16 | -42784807130635678 |
| 17 | 642457682754511906 |
| 18 | -9698259831536382826 |
| 19 | 147091417979841002294 |