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 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 13 |
| 5 | 71 |
| 6 | 461 |
| 7 | 3447 |
| 8 | 29093 |
| 9 | 272767 |
| 10 | 2797069 |
| 11 | 30897015 |
| 12 | 362691733 |
| 13 | 4475707535 |
| 14 | 57612706973 |
| 15 | 769779683367 |
| 16 | 10648337804645 |
| 17 | 152377871778559 |
| 18 | 2256813406989421 |
| 19 | 34636615303780503 |