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 | 2 |
| 3 | 3 |
| 4 | 8 |
| 5 | 18 |
| 6 | 60 |
| 7 | 232 |
| 8 | 1389 |
| 9 | 14174 |
| 10 | 291396 |
| 11 | 12307993 |
| 12 | 1031244083 |
| 13 | 166112993730 |
| 14 | 50667178220215 |
| 15 | 29104660317374991 |
| 16 | 31455540471012663839 |
| 17 | 64032442292149795841796 |
| 18 | 245999865227419158171980939 |
| 19 | 1787823661072649054474456291897 |
| 20 | 24639596830978183991220162941946112 |