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) |
|---|---|
| 4 | 4 |
| 5 | 90 |
| 6 | 1349 |
| 7 | 17220 |
| 8 | 203568 |
| 9 | 2312094 |
| 10 | 25691670 |
| 11 | 282000444 |
| 12 | 3074136464 |
| 13 | 33387698708 |
| 14 | 361969672904 |
| 15 | 3921901043440 |
| 16 | 42499598861832 |
| 17 | 460831546801414 |
| 18 | 5001468564165262 |
| 19 | 54341248085414380 |