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 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 16 |
| 5 | 90 |
| 6 | 597 |
| 7 | 4501 |
| 8 | 38216 |
| 9 | 361188 |
| 10 | 3764145 |
| 11 | 42904631 |
| 12 | 531137832 |
| 13 | 7098180830 |
| 14 | 101867469333 |
| 15 | 1562669432745 |
| 16 | 25519514490416 |
| 17 | 442059126085000 |
| 18 | 8096324154363009 |
| 19 | 156327367277971371 |
| 20 | 3173836404105603040 |
| 21 | 67593549458478576162 |
| 22 | 1506808374349969515253 |
| 23 | 35090063236144812165117 |