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 | -1 |
| 3 | -7 |
| 4 | 47 |
| 5 | 873 |
| 6 | -26433 |
| 7 | -1749159 |
| 8 | 220526159 |
| 9 | 56904690761 |
| 10 | -29022490524961 |
| 11 | -29777360924913095 |
| 12 | 60924625361199230575 |
| 13 | 249669263740090899509545 |
| 14 | -2044791574538659983034398465 |
| 15 | -33505955988983997787211823466215 |