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) |
|---|---|
| 1 | 121 |
| 2 | 804 |
| 3 | 6828 |
| 4 | 43456 |
| 5 | 284992 |
| 6 | 1473792 |
| 7 | 7616082 |
| 8 | 32986844 |
| 9 | 142361644 |
| 10 | 537301496 |
| 11 | 2020791427 |
| 12 | 6843417893 |
| 13 | 23099713493 |
| 14 | 71683038307 |
| 15 | 221767602558 |
| 16 | 640525984280 |
| 17 | 1844757869502 |
| 18 | 5018918602972 |
| 19 | 13619020527533 |
| 20 | 35234899933725 |