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 | 9 |
| 2 | 1 |
| 3 | 407 |
| 4 | 9474 |
| 5 | 194979 |
| 6 | 548834 |
| 7 | 14459929 |
| 8 | 88593477 |
| 9 | 912985153 |
| 10 | 4679307774 |
| 11 | 94204591914 |
| 12 | 1 |
| 13 | 564240140138 |
| 14 | 28116440335967 |
| 15 | 1 |
| 16 | 4338281769391371 |
| 17 | 35875699062250035 |
| 18 | 1 |
| 19 | 4929273885928088826 |
| 20 | 63105425988599693916 |