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 | 45 |
| 2 | 1260 |
| 3 | 28350 |
| 4 | 563031 |
| 5 | 10333575 |
| 6 | 179866170 |
| 7 | 3016747800 |
| 8 | 49263275061 |
| 9 | 788796913905 |
| 10 | 12445575859080 |
| 11 | 194186867360850 |
| 12 | 3004103990159091 |
| 13 | 46168557763591035 |
| 14 | 705914973500103990 |
| 15 | 10750288516418083500 |