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 | 0 |
| 1 | 1 |
| 2 | 6 |
| 3 | 27 |
| 4 | 113 |
| 5 | 464 |
| 6 | 1896 |
| 7 | 7738 |
| 8 | 31571 |
| 9 | 128800 |
| 10 | 525455 |
| 11 | 2143647 |
| 12 | 8745216 |
| 13 | 35676948 |
| 14 | 145547524 |
| 15 | 593775045 |
| 16 | 2422362078 |
| 17 | 9882257735 |
| 18 | 40315615409 |
| 19 | 164471408184 |
| 20 | 670976837020 |
| 21 | 2737314167774 |
| 22 | 11167134898975 |
| 23 | 45557394660800 |
| 24 | 185855747875875 |
| 25 | 758216295635151 |