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 | -15 |
| 3 | -66 |
| 4 | -54 |
| 5 | 725 |
| 6 | 4580 |
| 7 | 12739 |
| 8 | 3346 |
| 9 | -149076 |
| 10 | -791226 |
| 11 | -2182124 |
| 12 | -1656973 |
| 13 | 16553206 |
| 14 | 100646954 |
| 15 | 318795473 |
| 16 | 506196578 |
| 17 | -818806580 |
| 18 | -9148048880 |
| 19 | -36415709566 |
| 20 | -87180585636 |
| 21 | -70923559814 |
| 22 | 484810027389 |
| 23 | 2992082912770 |
| 24 | 9866919438716 |
| 25 | 19936695359140 |