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 | 1 |
| 3 | 1 |
| 4 | 25 |
| 5 | 121 |
| 6 | 361 |
| 7 | 841 |
| 8 | 42001 |
| 9 | 365905 |
| 10 | 1819441 |
| 11 | 6660721 |
| 12 | 498971881 |
| 13 | 6278929801 |
| 14 | 43710250585 |
| 15 | 218205219961 |
| 16 | 21795091762081 |
| 17 | 358652470233121 |
| 18 | 3210080802962401 |
| 19 | 20298322381652065 |
| 20 | 2534333270094778681 |
| 21 | 51516840824285500441 |
| 22 | 563561785768079119561 |