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 | 1 |
| 2 | 4 |
| 3 | 32 |
| 4 | 412 |
| 5 | 7626 |
| 6 | 189714 |
| 7 | 6056798 |
| 8 | 240007916 |
| 9 | 11508705154 |
| 10 | 654626405938 |
| 11 | 43464473224798 |
| 12 | 3324172407594044 |
| 13 | 289601772112074904 |
| 14 | 28468601550479894604 |
| 15 | 3132023322088403861412 |
| 16 | 382897150538947034202408 |
| 17 | 51691108594752337375636926 |
| 18 | 7663268227028277190563579522 |