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 | -450 |
| 3 | -39390 |
| 4 | -977730 |
| 5 | -14296428 |
| 6 | -143213310 |
| 7 | -1055712720 |
| 8 | -6025115970 |
| 9 | -27903841170 |
| 10 | -109691724204 |
| 11 | -379012525560 |
| 12 | -1175178073470 |
| 13 | -3321971658300 |
| 14 | -8707342384080 |
| 15 | -21376296671508 |
| 16 | -49403752829250 |
| 17 | -108646063965540 |
| 18 | -228747032737650 |
| 19 | -461282293976520 |
| 20 | -898676446989996 |