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 | -30 |
| 2 | 375 |
| 3 | -2350 |
| 4 | 5625 |
| 5 | 18594 |
| 6 | -159470 |
| 7 | 264000 |
| 8 | 897090 |
| 9 | -3531910 |
| 10 | -1435527 |
| 11 | 16983900 |
| 12 | 18552080 |
| 13 | -93541590 |
| 14 | -225801585 |
| 15 | 676209374 |
| 16 | 1172571840 |
| 17 | -2433574980 |
| 18 | -6300652790 |
| 19 | 673571550 |
| 20 | 37882244124 |