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 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 60 |
| 5 | 672 |
| 6 | 9953 |
| 7 | 184557 |
| 8 | 4142631 |
| 9 | 109813842 |
| 10 | 3373122370 |
| 11 | 118280690398 |
| 12 | 4678086540493 |
| 13 | 206625802351035 |
| 14 | 10107719377251109 |
| 15 | 543762148079927802 |
| 16 | 31975474310851749920 |
| 17 | 2044501883873268414092 |
| 18 | 141485408653554069693421 |