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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 3 |
| 4 | 14 |
| 5 | 195 |
| 6 | 2059 |
| 7 | 31150 |
| 8 | 489012 |
| 9 | 9073638 |
| 10 | 183490118 |
| 11 | 4135560660 |
| 12 | 101421574440 |
| 13 | 2706766547628 |
| 14 | 77860733488732 |
| 15 | 2405136817507216 |
| 16 | 79353915366944784 |
| 17 | 2786110796782734528 |
| 18 | 103703080088989729280 |
| 19 | 4079350129335095498048 |