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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 4 |
| 4 | -4 |
| 5 | 0 |
| 6 | 8 |
| 7 | -16 |
| 8 | 12 |
| 9 | 20 |
| 10 | -80 |
| 11 | 116 |
| 12 | -4 |
| 13 | -376 |
| 14 | 884 |
| 15 | -764 |
| 16 | -1308 |
| 17 | 5816 |
| 18 | -9128 |
| 19 | 648 |
| 20 | 32008 |
| 21 | -79608 |
| 22 | 73100 |
| 23 | 122020 |
| 24 | -574044 |
| 25 | 937456 |
| 26 | -97748 |
| 27 | -3366892 |
| 28 | 8659492 |
| 29 | -8276056 |
| 30 | -13301640 |
| 31 | 65261640 |
| 32 | -109501476 |
| 33 | 14857740 |
| 34 | 395316672 |
| 35 | -1042421076 |
| 36 | 1028105156 |
| 37 | 1582877768 |
| 38 | -8052459580 |