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 | 6 |
| 3 | 39 |
| 4 | 292 |
| 5 | 2505 |
| 6 | 24306 |
| 7 | 263431 |
| 8 | 3154824 |
| 9 | 41368977 |
| 10 | 589410910 |
| 11 | 9064804551 |
| 12 | 149641946796 |
| 13 | 2638693215769 |
| 14 | 49490245341642 |
| 15 | 983607047803815 |
| 16 | 20646947498718736 |
| 17 | 456392479671188001 |
| 18 | 10595402429677269174 |
| 19 | 257723100178182605287 |
| 20 | 6553958557721713088820 |