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 | 2 |
| 3 | 2 |
| 4 | -1 |
| 5 | -4 |
| 6 | 7 |
| 7 | 33 |
| 8 | -5 |
| 9 | -200 |
| 10 | -151 |
| 11 | 1185 |
| 12 | 2202 |
| 13 | -6069 |
| 14 | -21799 |
| 15 | 21791 |
| 16 | 182718 |
| 17 | 26520 |
| 18 | -1349611 |
| 19 | -1613331 |
| 20 | 8674338 |
| 21 | 21651795 |
| 22 | -44750412 |
| 23 | -217666394 |
| 24 | 121538304 |
| 25 | 1859974399 |
| 26 | 1023915107 |
| 27 | -13828122997 |
| 28 | -23155237537 |
| 29 | 86925632115 |
| 30 | 282182920662 |