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 | -2 |
| 2 | -3 |
| 3 | -8 |
| 4 | -28 |
| 5 | -112 |
| 6 | -484 |
| 7 | -2200 |
| 8 | -10364 |
| 9 | -50144 |
| 10 | -247684 |
| 11 | -1243816 |
| 12 | -6331164 |
| 13 | -32591184 |
| 14 | -169376484 |
| 15 | -887465784 |
| 16 | -4682990076 |
| 17 | -24864759744 |
| 18 | -132745182724 |
| 19 | -712136879944 |
| 20 | -3837043171100 |
| 21 | -20755343638064 |
| 22 | -112668274522852 |
| 23 | -613581530620888 |
| 24 | -3351355226348668 |
| 25 | -18354390999804832 |
| 26 | -100771410237846404 |
| 27 | -554536090460808680 |