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 | 6 |
| 2 | 58 |
| 3 | 624 |
| 4 | 7050 |
| 5 | 81926 |
| 6 | 969640 |
| 7 | 11624976 |
| 8 | 140708682 |
| 9 | 1715727090 |
| 10 | 21043480458 |
| 11 | 259331888712 |
| 12 | 3208566672792 |
| 13 | 39830312782344 |
| 14 | 495853462219600 |
| 15 | 6188170518911264 |
| 16 | 77393543796042570 |
| 17 | 969771226630919754 |
| 18 | 12172039459124750062 |
| 19 | 153006230384961477600 |
| 20 | 1925930502301667496250 |