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 | -2 |
| 3 | -2 |
| 4 | 8 |
| 5 | 88 |
| 6 | 592 |
| 7 | 3344 |
| 8 | 14464 |
| 9 | 2944 |
| 10 | -1121536 |
| 11 | -21603584 |
| 12 | -317969408 |
| 13 | -4202380288 |
| 14 | -51322677248 |
| 15 | -562045749248 |
| 16 | -4751724347392 |
| 17 | -3419742961664 |
| 18 | 1260396818661376 |
| 19 | 45221885372727296 |
| 20 | 1218206507254153216 |
| 21 | 29421299633821057024 |
| 22 | 669044215287581769728 |
| 23 | 14528992234596624498688 |