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 | 7 |
| 4 | -14 |
| 5 | 54 |
| 6 | -1112 |
| 7 | 6574 |
| 8 | -48488 |
| 9 | 1143731 |
| 10 | -14813072 |
| 11 | 16252211 |
| 12 | -3500388967 |
| 13 | 125127865048 |
| 14 | -158589803803 |
| 15 | 33133618166566 |
| 16 | -30512906279732 |
| 17 | 4378989933312913 |
| 18 | -330336346477870319 |
| 19 | 1981395373839282068 |
| 20 | -251479418962683770473 |
| 21 | 79893293800974935213 |
| 22 | -31493610597939643431532 |