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 | 0 |
| 1 | 1 |
| 2 | 1057 |
| 3 | 68125 |
| 4 | 1399325 |
| 5 | 15227450 |
| 6 | 110102426 |
| 7 | 597639882 |
| 8 | 2621915850 |
| 9 | 9756511275 |
| 10 | 31839011275 |
| 11 | 93340522951 |
| 12 | 250280856007 |
| 13 | 622316813300 |
| 14 | 1450471654100 |
| 15 | 3196426654100 |
| 16 | 6706824221076 |
| 17 | 13476181309557 |
| 18 | 26055415288725 |
| 19 | 48670370285425 |
| 20 | 88136930285425 |
| 21 | 155187254126926 |