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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 10 |
| 6 | 65 |
| 7 | 350 |
| 8 | 1700 |
| 9 | 7770 |
| 10 | 34095 |
| 11 | 145750 |
| 12 | 611435 |
| 13 | 2532530 |
| 14 | 10391395 |
| 15 | 42355940 |
| 16 | 171797200 |
| 17 | 694337290 |
| 18 | 2798799150 |
| 19 | 11259666950 |
| 20 | 45232081795 |
| 21 | 181509069700 |
| 22 | 727778478075 |
| 23 | 2916342574750 |
| 24 | 11681056021300 |
| 25 | 46771289738800 |
| 26 | 187226354413735 |
| 27 | 749329038527580 |