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 | 21 |
| 4 | 79 |
| 5 | 308 |
| 6 | 1219 |
| 7 | 4826 |
| 8 | 18857 |
| 9 | 71574 |
| 10 | 257553 |
| 11 | 837114 |
| 12 | 2140496 |
| 13 | 1379550 |
| 14 | -35589730 |
| 15 | -370646635 |
| 16 | -2719034151 |
| 17 | -17429175486 |
| 18 | -103771133876 |
| 19 | -588804389677 |
| 20 | -3225403649859 |
| 21 | -17180039158530 |
| 22 | -89342552789741 |
| 23 | -454604059204324 |
| 24 | -2265246385921936 |