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 | 3 |
| 3 | 75 |
| 4 | 1435 |
| 5 | 25515 |
| 6 | 436821 |
| 7 | 7339332 |
| 8 | 121782375 |
| 9 | 2005392675 |
| 10 | 32835436777 |
| 11 | 535550923908 |
| 12 | 8707954925033 |
| 13 | 141270179732500 |
| 14 | 2287544190032700 |
| 15 | 36988236910737360 |
| 16 | 597341791692978975 |
| 17 | 9637351741503033075 |
| 18 | 155353556752487795625 |
| 19 | 2502545930175392062500 |