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 | 708 |
| 4 | 24961 |
| 5 | 1682688 |
| 6 | 220959136 |
| 7 | 57266675520 |
| 8 | 29497077110720 |
| 9 | 30294634141775360 |
| 10 | 62134850895148484608 |
| 11 | 254691311135373319017472 |
| 12 | 2087196424913845641682560512 |
| 13 | 34202892422993270952623113994240 |
| 14 | 1120863025258656246362522776511881216 |
| 15 | 73460242428855296330451249854756580540416 |