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 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 34 |
| 5 | 387 |
| 6 | 5686 |
| 7 | 102084 |
| 8 | 2162168 |
| 9 | 52693975 |
| 10 | 1450876804 |
| 11 | 44509105965 |
| 12 | 1504709144203 |
| 13 | 55563209785167 |
| 14 | 2224667253972242 |
| 15 | 95984473918245388 |
| 16 | 4439157388017620554 |
| 17 | 219067678811211857307 |
| 18 | 11489425098298623161164 |
| 19 | 638159082104453330569185 |