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 | 1 |
| 1 | 7 |
| 2 | 48 |
| 3 | 431 |
| 4 | 3840 |
| 5 | 32143 |
| 6 | 260848 |
| 7 | 2094751 |
| 8 | 16773120 |
| 9 | 134211167 |
| 10 | 1073731824 |
| 11 | 8589919951 |
| 12 | 68719456000 |
| 13 | 549755785327 |
| 14 | 4398046472688 |
| 15 | 35184372038207 |
| 16 | 281474976645120 |
| 17 | 2251799813601727 |
| 18 | 18014398509377008 |