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) |
|---|---|
| 1 | 1 |
| 2 | -4 |
| 3 | 10 |
| 4 | -24 |
| 5 | 59 |
| 6 | -146 |
| 7 | 360 |
| 8 | -886 |
| 9 | 2182 |
| 10 | -5376 |
| 11 | 13244 |
| 12 | -32624 |
| 13 | 80364 |
| 14 | -197968 |
| 15 | 487672 |
| 16 | -1201319 |
| 17 | 2959297 |
| 18 | -7289859 |
| 19 | 17957662 |
| 20 | -44236464 |
| 21 | 108971015 |
| 22 | -268436517 |
| 23 | 661259918 |
| 24 | -1628931424 |
| 25 | 4012669610 |
| 26 | -9884711639 |
| 27 | 24349755585 |
| 28 | -59982589144 |
| 29 | 147759635098 |