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) |
|---|---|
| 2 | 1 |
| 3 | 3 |
| 4 | 8 |
| 5 | 5 |
| 6 | -156 |
| 7 | -1253 |
| 8 | 48 |
| 9 | 116937 |
| 10 | 1236140 |
| 11 | -4517689 |
| 12 | -317599800 |
| 13 | -3473788019 |
| 14 | 43408737540 |
| 15 | 2033846838675 |
| 16 | 19004486417504 |
| 17 | -643679274285679 |
| 18 | -24665731809676452 |
| 19 | -135665006897593601 |
| 20 | 15018201730467027960 |