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 | 18 |
| 3 | 112 |
| 4 | 692 |
| 5 | 4294 |
| 6 | 26624 |
| 7 | 165086 |
| 8 | 1023662 |
| 9 | 6347440 |
| 10 | 39358774 |
| 11 | 244053158 |
| 12 | 1513307844 |
| 13 | 9383614226 |
| 14 | 58185263358 |
| 15 | 360791140032 |
| 16 | 2237168644134 |
| 17 | 13872079956206 |
| 18 | 86017029971684 |
| 19 | 533368425534858 |
| 20 | 3307273890427894 |
| 21 | 20507514248408832 |
| 22 | 127161570097317790 |