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 | 0 |
| 2 | -2 |
| 3 | -8 |
| 4 | -26 |
| 5 | -80 |
| 6 | -244 |
| 7 | -752 |
| 8 | -2362 |
| 9 | -7584 |
| 10 | -24892 |
| 11 | -83376 |
| 12 | -284324 |
| 13 | -984672 |
| 14 | -3455144 |
| 15 | -12259168 |
| 16 | -43908026 |
| 17 | -158531392 |
| 18 | -576352364 |
| 19 | -2107982128 |
| 20 | -7750490636 |
| 21 | -28629222112 |
| 22 | -106190978264 |
| 23 | -395347083808 |
| 24 | -1476813394916 |
| 25 | -5533435084480 |
| 26 | -20790762971864 |
| 27 | -78316232088032 |