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 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 24 |
| 6 | 118 |
| 7 | 686 |
| 8 | 4598 |
| 9 | 34872 |
| 10 | 295044 |
| 11 | 2753958 |
| 12 | 28103804 |
| 13 | 311216626 |
| 14 | 3716341042 |
| 15 | 47597786154 |
| 16 | 650812077852 |
| 17 | 9461423560788 |
| 18 | 145724617925326 |
| 19 | 2370293673319292 |
| 20 | 40600119927220706 |
| 21 | 730458115445479734 |