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 | 1 |
| 2 | 6 |
| 3 | 30 |
| 4 | 145 |
| 5 | 733 |
| 6 | 3540 |
| 7 | 17300 |
| 8 | 84479 |
| 9 | 411963 |
| 10 | 2011408 |
| 11 | 9816506 |
| 12 | 47911847 |
| 13 | 233851991 |
| 14 | 1141365064 |
| 15 | 5570761346 |
| 16 | 27189615925 |
| 17 | 132706261547 |
| 18 | 647709321582 |
| 19 | 3161321546320 |
| 20 | 15429691961077 |
| 21 | 75308819284819 |
| 22 | 367565220881250 |
| 23 | 1794002281279416 |
| 24 | 8756117243124305 |
| 25 | 42736617464745197 |