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 | 49 |
| 3 | 392 |
| 4 | 2793 |
| 5 | 19600 |
| 6 | 137249 |
| 7 | 960792 |
| 8 | 6725593 |
| 9 | 47079200 |
| 10 | 329554449 |
| 11 | 2306881192 |
| 12 | 16148168393 |
| 13 | 113037178800 |
| 14 | 791260251649 |
| 15 | 5538821761592 |
| 16 | 38771752331193 |
| 17 | 271402266318400 |
| 18 | 1899815864228849 |
| 19 | 13298711049601992 |
| 20 | 93090977347213993 |