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 | 4 |
| 2 | 9 |
| 3 | 8 |
| 4 | -31 |
| 5 | -180 |
| 6 | -503 |
| 7 | -752 |
| 8 | 513 |
| 9 | 7316 |
| 10 | 25673 |
| 11 | 51480 |
| 12 | 26209 |
| 13 | -255524 |
| 14 | -1205559 |
| 15 | -3033568 |
| 16 | -3695359 |
| 17 | 6453540 |
| 18 | 51681673 |
| 19 | 161551912 |
| 20 | 284435937 |
| 21 | 6880364 |
| 22 | -1963530103 |
| 23 | -7902282960 |
| 24 | -17864421119 |
| 25 | -16141703756 |
| 26 | 60484132809 |