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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 25 |
| 5 | 137 |
| 6 | 1019 |
| 7 | 2143 |
| 8 | 6709 |
| 9 | 76319 |
| 10 | 1019867 |
| 11 | 2084779 |
| 12 | 36161963 |
| 13 | 699329537 |
| 14 | 16317371911 |
| 15 | 82657705331 |
| 16 | 250947687593 |
| 17 | 7357796373397 |
| 18 | 230420777138107 |
| 19 | 465354165304139 |
| 20 | 17362507669146743 |
| 21 | 717205745892079663 |