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) |
|---|---|
| 2 | 9 |
| 3 | 180 |
| 4 | 2070 |
| 5 | 17775 |
| 6 | 125865 |
| 7 | 773766 |
| 8 | 4260645 |
| 9 | 21453975 |
| 10 | 100250100 |
| 11 | 439479198 |
| 12 | 1822654251 |
| 13 | 7198716870 |
| 14 | 27221451885 |
| 15 | 98988000120 |
| 16 | 347428124352 |
| 17 | 1180620288702 |
| 18 | 3894719205510 |
| 19 | 12501561121560 |
| 20 | 39124469772495 |