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 | -3 |
| 3 | -23 |
| 4 | 233 |
| 5 | 3521 |
| 6 | -62171 |
| 7 | -1416407 |
| 8 | 35880977 |
| 9 | 1095318721 |
| 10 | -36224195059 |
| 11 | -1387587617239 |
| 12 | 56675849155705 |
| 13 | 2612993427672577 |
| 14 | -127090039302776395 |
| 15 | -6852033608852338199 |
| 16 | 386750643197222855969 |
| 17 | 23875394847093826450049 |