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 | 1 |
| 2 | 6 |
| 3 | 55 |
| 4 | 600 |
| 5 | 7946 |
| 6 | 123480 |
| 7 | 2208492 |
| 8 | 44710272 |
| 9 | 1011177360 |
| 10 | 25274905920 |
| 11 | 692042185440 |
| 12 | 20602098316800 |
| 13 | 662620120237440 |
| 14 | 22898921925035520 |
| 15 | 846245264387040000 |
| 16 | 33303963647943475200 |
| 17 | 1390631677349880268800 |
| 18 | 61407154400075559936000 |
| 19 | 2859166138267857522585600 |