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 | 6 |
| 2 | 42 |
| 3 | 284 |
| 4 | 1938 |
| 5 | 13188 |
| 6 | 89828 |
| 7 | 611640 |
| 8 | 4165218 |
| 9 | 28363252 |
| 10 | 193145388 |
| 11 | 1315249800 |
| 12 | 8956413716 |
| 13 | 60990068520 |
| 14 | 415321615368 |
| 15 | 2828197518960 |
| 16 | 19259058052098 |
| 17 | 131147584691796 |
| 18 | 893070155862492 |
| 19 | 6081501856336488 |
| 20 | 41412945154765212 |
| 21 | 282007973308889592 |