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 | 2 |
| 2 | -6 |
| 3 | 58 |
| 4 | -574 |
| 5 | 6402 |
| 6 | -75878 |
| 7 | 939290 |
| 8 | -12000318 |
| 9 | 157050178 |
| 10 | -2094657926 |
| 11 | 28368411194 |
| 12 | -389079656446 |
| 13 | 5393118559938 |
| 14 | -75431624084838 |
| 15 | 1063251390845338 |
| 16 | -15088643098754942 |
| 17 | 215396586102923138 |
| 18 | -3091050571516120582 |
| 19 | 44566089825496186170 |