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 | 1 |
| 2 | 7 |
| 3 | 58 |
| 4 | 531 |
| 5 | 5226 |
| 6 | 54598 |
| 7 | 601924 |
| 8 | 6985987 |
| 9 | 85328266 |
| 10 | 1097775922 |
| 11 | 14897635468 |
| 12 | 213581648046 |
| 13 | 3238686925956 |
| 14 | 51972937713900 |
| 15 | 882473430354888 |
| 16 | 15839021166164451 |
| 17 | 300037212548146890 |
| 18 | 5986554523174314490 |
| 19 | 125537613562829696828 |
| 20 | 2760474045847159393466 |