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 | 12 |
| 3 | 92 |
| 4 | 672 |
| 5 | 4652 |
| 6 | 31032 |
| 7 | 201812 |
| 8 | 1288992 |
| 9 | 8124572 |
| 10 | 50700552 |
| 11 | 313968932 |
| 12 | 1932641712 |
| 13 | 11839990892 |
| 14 | 72260648472 |
| 15 | 439667406452 |
| 16 | 2668522016832 |
| 17 | 16163719991612 |
| 18 | 97745259402792 |
| 19 | 590286253682372 |
| 20 | 3560791008422352 |