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 | 3 |
| 1 | 1 |
| 2 | 3 |
| 3 | -1390 |
| 4 | -139895 |
| 5 | 2064875400 |
| 6 | 999912530925 |
| 7 | -128585633463727440 |
| 8 | -176876516433064573125 |
| 9 | 109242473594498195269718400 |
| 10 | 333170810414553853376721961875 |
| 11 | -698025623281503752808511373154720000 |
| 12 | -4073023833462008382211035330291042675375 |