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 | 1 |
| 3 | 2 |
| 4 | -1 |
| 5 | -6 |
| 6 | 109 |
| 7 | 1154 |
| 8 | -2507 |
| 9 | 18392 |
| 10 | 829181 |
| 11 | 6383244 |
| 12 | -2209703 |
| 13 | -107812394 |
| 14 | 4571476337 |
| 15 | 317794760230 |
| 16 | 2764096980201 |
| 17 | -15873576166552 |
| 18 | 100411162138201 |
| 19 | 7249400365091352 |
| 20 | 111212112152829597 |
| 21 | 8121369858513002698 |
| 22 | 171335979252872509109 |
| 23 | 502729844835525379706 |