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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 3 |
| 4 | 21 |
| 5 | 39 |
| 6 | 285 |
| 7 | 309 |
| 8 | 1638 |
| 9 | 3099 |
| 10 | 14109 |
| 11 | 17157 |
| 12 | 135918 |
| 13 | 130995 |
| 14 | 789819 |
| 15 | 1791447 |
| 16 | 5425938 |
| 17 | 8047839 |
| 18 | 64463793 |
| 19 | 64486017 |
| 20 | 437310162 |
| 21 | 871626729 |
| 22 | 3136882659 |
| 23 | 4278115101 |
| 24 | 35355495078 |
| 25 | 42359479599 |