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 | -3 |
| 3 | -19 |
| 4 | -211 |
| 5 | -3301 |
| 6 | -66581 |
| 7 | -1643587 |
| 8 | -47986247 |
| 9 | -1617313033 |
| 10 | -61796668969 |
| 11 | -2639583958111 |
| 12 | -124635062782187 |
| 13 | -6446216079166189 |
| 14 | -362427406400015165 |
| 15 | -22008570202561166491 |
| 16 | -1435560535563493528591 |
| 17 | -100100185675457848764433 |
| 18 | -7430481272601559979203409 |