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 | 11 |
| 5 | 49 |
| 6 | 259 |
| 7 | 1593 |
| 8 | 11227 |
| 9 | 89537 |
| 10 | 799475 |
| 11 | 7917897 |
| 12 | 86257643 |
| 13 | 1025959345 |
| 14 | 13234866787 |
| 15 | 184078090137 |
| 16 | 2746061570587 |
| 17 | 43736283267137 |
| 18 | 740674930879379 |
| 19 | 13289235961616937 |
| 20 | 251805086618856395 |
| 21 | 5024288943352588369 |
| 22 | 105295629327037117123 |