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 | 405 |
| 3 | -3190 |
| 4 | 15660 |
| 5 | -45036 |
| 6 | 40745 |
| 7 | 222750 |
| 8 | -974835 |
| 9 | 1334580 |
| 10 | 1547469 |
| 11 | -8174520 |
| 12 | 8380245 |
| 13 | 9200250 |
| 14 | -23243355 |
| 15 | -2643380 |
| 16 | 14704740 |
| 17 | 82050570 |
| 18 | -116275500 |
| 19 | -195804810 |
| 20 | 442809990 |
| 21 | 25147930 |
| 22 | -371898000 |
| 23 | -313802910 |
| 24 | 125394405 |
| 25 | 1688931000 |
| 26 | -1364323095 |
| 27 | -737497840 |
| 28 | 158838945 |
| 29 | -1653918750 |
| 30 | 6309965146 |
| 31 | -1076120370 |