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 | 0 |
| 3 | 0 |
| 4 | 5 |
| 5 | 780 |
| 6 | 41545 |
| 7 | 1442910 |
| 8 | 39400305 |
| 9 | 923889960 |
| 10 | 19550316665 |
| 11 | 384954289170 |
| 12 | 7196416532305 |
| 13 | 129495073447740 |
| 14 | 2264887575116985 |
| 15 | 38775513868485030 |
| 16 | 653195404307491505 |
| 17 | 10869004241198535120 |
| 18 | 179171681947204584505 |
| 19 | 2932562923651659410490 |
| 20 | 47737465871974206925905 |