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) |
|---|---|
| 18 | 1 |
| 19 | -18 |
| 20 | 153 |
| 21 | -816 |
| 22 | 3042 |
| 23 | -8262 |
| 24 | 16098 |
| 25 | -19278 |
| 26 | -1377 |
| 27 | 72556 |
| 28 | -203184 |
| 29 | 339030 |
| 30 | -326961 |
| 31 | -53244 |
| 32 | 940050 |
| 33 | -2147916 |
| 34 | 2975391 |
| 35 | -2293488 |
| 36 | -911369 |
| 37 | 6616332 |
| 38 | -12906162 |
| 39 | 15883884 |
| 40 | -10936899 |
| 41 | -4660974 |
| 42 | 28758849 |
| 43 | -52660134 |
| 44 | 62518248 |
| 45 | -44501988 |
| 46 | -7465464 |
| 47 | 84565242 |