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 | 3 |
| 2 | 15 |
| 3 | 84 |
| 4 | 321 |
| 5 | -2157 |
| 6 | -57126 |
| 7 | -23496 |
| 8 | 19229199 |
| 9 | 114026754 |
| 10 | -14369595177 |
| 11 | -124727102772 |
| 12 | 21679898019936 |
| 13 | 89714147328354 |
| 14 | -57010454409251982 |
| 15 | 653678598376462566 |
| 16 | 223463102168891738085 |
| 17 | -9691395708350731626375 |
| 18 | -1087655068021435814109648 |