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 | 4 |
| 2 | 38 |
| 3 | 582 |
| 4 | 12354 |
| 5 | 335730 |
| 6 | 11127150 |
| 7 | 435300390 |
| 8 | 19633815810 |
| 9 | 1003121039970 |
| 10 | 57259773499950 |
| 11 | 3611583223860150 |
| 12 | 249441581246630850 |
| 13 | 18723487284033181650 |
| 14 | 1517668796159163197550 |
| 15 | 132117536404977132759750 |