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 | 0 |
| 2 | 9 |
| 3 | 48 |
| 4 | 554 |
| 5 | 3334 |
| 6 | 30837 |
| 7 | 202363 |
| 8 | 1733660 |
| 9 | 12139768 |
| 10 | 99907487 |
| 11 | 729039938 |
| 12 | 5866737162 |
| 13 | 43944684689 |
| 14 | 349284676982 |
| 15 | 2660349798813 |
| 16 | 21006556689388 |
| 17 | 161738436141669 |
| 18 | 1272996087653588 |
| 19 | 9871903975910464 |
| 20 | 77596716393162478 |