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 | 1 |
| 2 | 0 |
| 3 | -2 |
| 4 | -5 |
| 5 | -4 |
| 6 | 4 |
| 7 | 21 |
| 8 | 35 |
| 9 | 23 |
| 10 | -47 |
| 11 | -165 |
| 12 | -239 |
| 13 | -78 |
| 14 | 479 |
| 15 | 1273 |
| 16 | 1508 |
| 17 | -138 |
| 18 | -4429 |
| 19 | -9451 |
| 20 | -8845 |
| 21 | 6207 |
| 22 | 37937 |
| 23 | 67123 |
| 24 | 45144 |
| 25 | -83355 |
| 26 | -308078 |
| 27 | -455109 |
| 28 | -166872 |
| 29 | 873799 |
| 30 | 2393041 |
| 31 | 2916869 |
| 32 | -73472 |
| 33 | -8133572 |
| 34 | -17828640 |
| 35 | -17294146 |
| 36 | 10383571 |
| 37 | 70275162 |
| 38 | 127401305 |
| 39 | 90368779 |
| 40 | -147825714 |