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 | 4 |
| 2 | 22 |
| 3 | 158 |
| 4 | 1408 |
| 5 | 15002 |
| 6 | 186100 |
| 7 | 2634998 |
| 8 | 41937136 |
| 9 | 741170834 |
| 10 | 14402727484 |
| 11 | 305225470046 |
| 12 | 7005711916840 |
| 13 | 173134991854970 |
| 14 | 4583675648417044 |
| 15 | 129424786945875398 |
| 16 | 3882446011526729440 |
| 17 | 123304773913531035170 |
| 18 | 4133369745467043807340 |
| 19 | 145840627118145774415214 |