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 | -1 |
| 3 | -1 |
| 4 | 11 |
| 5 | 31 |
| 6 | 19 |
| 7 | -41 |
| 8 | 11 |
| 9 | 431 |
| 10 | 899 |
| 11 | 199 |
| 12 | -1349 |
| 13 | 1951 |
| 14 | 15539 |
| 15 | 24119 |
| 16 | -5269 |
| 17 | -36209 |
| 18 | 115939 |
| 19 | 522919 |
| 20 | 583451 |
| 21 | -459649 |
| 22 | -696301 |
| 23 | 5336599 |
| 24 | 16510411 |
| 25 | 11941231 |
| 26 | -20545981 |
| 27 | -1202041 |
| 28 | 215199611 |
| 29 | 488443231 |
| 30 | 164515699 |
| 31 | -715515401 |
| 32 | 773905451 |
| 33 | 7930934351 |