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) |
|---|---|
| 4 | 1 |
| 5 | 10 |
| 6 | 85 |
| 7 | 735 |
| 8 | 6769 |
| 9 | 67284 |
| 10 | 723680 |
| 11 | 8409500 |
| 12 | 105258076 |
| 13 | 1414014888 |
| 14 | 20313753096 |
| 15 | 310989260400 |
| 16 | 5056995703824 |
| 17 | 87077748875904 |
| 18 | 1583313975727488 |
| 19 | 30321254007719424 |
| 20 | 610116075740491776 |