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 | 11 |
| 2 | 81 |
| 3 | 621 |
| 4 | 4741 |
| 5 | 36211 |
| 6 | 276561 |
| 7 | 2112241 |
| 8 | 16132281 |
| 9 | 123210611 |
| 10 | 941023441 |
| 11 | 7187084861 |
| 12 | 54891500621 |
| 13 | 419234905211 |
| 14 | 3201914754721 |
| 15 | 24454686308481 |
| 16 | 186773143027761 |
| 17 | 1426483517982011 |
| 18 | 10894795654704401 |
| 19 | 83209214029813101 |
| 20 | 635511992964231701 |
| 21 | 4853735225243983011 |