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 | 8 |
| 2 | 40 |
| 3 | 188 |
| 4 | 880 |
| 5 | 4148 |
| 6 | 19720 |
| 7 | 94508 |
| 8 | 456160 |
| 9 | 2215268 |
| 10 | 10814200 |
| 11 | 53022428 |
| 12 | 260917840 |
| 13 | 1287811988 |
| 14 | 6371951080 |
| 15 | 31591319948 |
| 16 | 156882857920 |
| 17 | 780119322308 |
| 18 | 3883416742360 |
| 19 | 19348364235068 |
| 20 | 96466943268400 |
| 21 | 481235204714228 |