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 | 1 |
| 3 | 5 |
| 4 | 31 |
| 5 | 246 |
| 6 | 2353 |
| 7 | 26585 |
| 8 | 345775 |
| 9 | 5094220 |
| 10 | 83833256 |
| 11 | 1524414737 |
| 12 | 30353430420 |
| 13 | 656851828075 |
| 14 | 15350023574061 |
| 15 | 385261255931365 |
| 16 | 10335781852020335 |
| 17 | 295166535640444376 |
| 18 | 8939894824857438940 |
| 19 | 286234265613041061128 |
| 20 | 9659753724363828753408 |