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 | 3 |
| 2 | 15 |
| 3 | 105 |
| 4 | 1155 |
| 5 | 15015 |
| 6 | 255255 |
| 7 | 4849845 |
| 8 | 140645505 |
| 9 | 4360010655 |
| 10 | 178760436855 |
| 11 | 7686698784765 |
| 12 | 453515228301135 |
| 13 | 27664428926369235 |
| 14 | 1964174453772215685 |
| 15 | 143384735125371745005 |
| 16 | 14481858247662546245505 |