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 | -6 |
| 2 | 407 |
| 3 | -357 |
| 4 | 41483 |
| 5 | -30583 |
| 6 | 21019289 |
| 7 | -1997177 |
| 8 | 200758163 |
| 9 | -141000363 |
| 10 | 125429769517 |
| 11 | -4618718797 |
| 12 | 86138583685913 |
| 13 | -1694601277343 |
| 14 | -67473161580433 |
| 15 | 636736947594783 |
| 16 | 1156482071227275091 |
| 17 | -457643653454013523 |
| 18 | -6761158493790100610029 |
| 19 | 395155414869373487563 |