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 | 0 |
| 4 | 33 |
| 5 | 339 |
| 6 | 2881 |
| 7 | 25099 |
| 8 | 215804 |
| 9 | 1846097 |
| 10 | 15888305 |
| 11 | 137715130 |
| 12 | 1202533145 |
| 13 | 10576414202 |
| 14 | 93649741408 |
| 15 | 834451865580 |
| 16 | 7478286927272 |
| 17 | 67376249426987 |
| 18 | 609996708149171 |