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 | 1 |
| 2 | 3 |
| 3 | 15 |
| 4 | 112 |
| 5 | 1165 |
| 6 | 15966 |
| 7 | 275149 |
| 8 | 5743032 |
| 9 | 141020793 |
| 10 | 3984082570 |
| 11 | 127298787121 |
| 12 | 4538547029556 |
| 13 | 178610366328277 |
| 14 | 7690287949961358 |
| 15 | 359592884584517445 |
| 16 | 18146340023779538416 |
| 17 | 982966789391874234865 |
| 18 | 56889414275458791370770 |
| 19 | 3503393307156206473624153 |
| 20 | 228738978280736413137020460 |