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 | 6 |
| 4 | 29 |
| 5 | 202 |
| 6 | 1880 |
| 7 | 22108 |
| 8 | 315784 |
| 9 | 5322126 |
| 10 | 103541022 |
| 11 | 2285965792 |
| 12 | 56501970700 |
| 13 | 1546339364952 |
| 14 | 46433615292128 |
| 15 | 1518172222889000 |
| 16 | 53695946069029290 |
| 17 | 2042960241832903824 |
| 18 | 83207255745283689726 |
| 19 | 3612360848988984098484 |
| 20 | 166537270023045091100852 |
| 21 | 8125771150231992039148508 |