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 | 7 |
| 3 | 73 |
| 4 | 861 |
| 5 | 11112 |
| 6 | 151828 |
| 7 | 2159179 |
| 8 | 31627690 |
| 9 | 473917665 |
| 10 | 7230164079 |
| 11 | 111926802631 |
| 12 | 1753762735460 |
| 13 | 27760507986844 |
| 14 | 443257137593369 |
| 15 | 7130838718144623 |
| 16 | 115469073853104486 |
| 17 | 1880570694656739472 |
| 18 | 30784302913287253256 |
| 19 | 506228988080918570208 |
| 20 | 8358750672258509735440 |
| 21 | 138528877561300962357350 |