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 | 5 |
| 1 | 30 |
| 2 | 162 |
| 3 | 850 |
| 4 | 4425 |
| 5 | 22995 |
| 6 | 119560 |
| 7 | 622512 |
| 8 | 3246750 |
| 9 | 16963375 |
| 10 | 88779900 |
| 11 | 465386220 |
| 12 | 2443204946 |
| 13 | 12844119225 |
| 14 | 67608235800 |
| 15 | 356288599640 |
| 16 | 1879625199825 |
| 17 | 9925931817045 |
| 18 | 52464942758250 |
| 19 | 277546278287250 |