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 | 20 |
| 4 | 193 |
| 5 | 2282 |
| 6 | 29989 |
| 7 | 510452 |
| 8 | 9699613 |
| 9 | 223092770 |
| 10 | 6469693101 |
| 11 | 200560489970 |
| 12 | 7420738134613 |
| 13 | 304250263526972 |
| 14 | 13082761331669749 |
| 15 | 614889782588491082 |
| 16 | 32589158477190044349 |
| 17 | 1922760350154212638630 |
| 18 | 117288381359406970982769 |
| 19 | 7858321551080267055878522 |