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 | 11 |
| 3 | 51 |
| 4 | 255 |
| 5 | 1325 |
| 6 | 7039 |
| 7 | 37951 |
| 8 | 206799 |
| 9 | 1135969 |
| 10 | 6279509 |
| 11 | 34889553 |
| 12 | 194664283 |
| 13 | 1089943229 |
| 14 | 6120967411 |
| 15 | 34463104999 |
| 16 | 194474062663 |
| 17 | 1099571123853 |
| 18 | 6227893795649 |
| 19 | 35329149864161 |
| 20 | 200691916063033 |
| 21 | 1141489886332555 |