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 | 6 |
| 2 | 54 |
| 3 | 486 |
| 4 | 4374 |
| 5 | 39366 |
| 6 | 354294 |
| 7 | 3188646 |
| 8 | 28697814 |
| 9 | 258280326 |
| 10 | 2324522934 |
| 11 | 20920706406 |
| 12 | 188286357654 |
| 13 | 1694577218886 |
| 14 | 15251194969974 |
| 15 | 137260754729766 |
| 16 | 1235346792567894 |
| 17 | 11118121133111046 |
| 18 | 100063090197999414 |
| 19 | 900567811781994726 |
| 20 | 8105110306037952534 |