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 | -7 |
| 5 | -14 |
| 6 | 13 |
| 7 | 113 |
| 8 | 337 |
| 9 | 19 |
| 10 | -2579 |
| 11 | -10867 |
| 12 | -9911 |
| 13 | 71852 |
| 14 | 431229 |
| 15 | 741181 |
| 16 | -2178783 |
| 17 | -20081708 |
| 18 | -51012467 |
| 19 | 58414532 |
| 20 | 1061935641 |
| 21 | 3651310699 |
| 22 | 1841181 |
| 23 | -62090909433 |
| 24 | -279070619279 |
| 25 | -250335322449 |
| 26 | 3913178936941 |
| 27 | 22877592319648 |
| 28 | 38634162528361 |