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 | 90 |
| 2 | -5940 |
| 3 | 758520 |
| 4 | -115431930 |
| 5 | 19355028840 |
| 6 | -3447208777320 |
| 7 | 639751846440960 |
| 8 | -122326632902618100 |
| 9 | 23925871041887048130 |
| 10 | -4763590542726586318440 |
| 11 | 962102309316632909723880 |
| 12 | -196619722885250960565506040 |
| 13 | 40580696990507644723354537320 |