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) |
|---|---|
| 1 | 0 |
| 2 | 5 |
| 3 | 260 |
| 4 | 2289 |
| 5 | 4991 |
| 6 | 7020 |
| 7 | 94635 |
| 8 | 5103280 |
| 9 | 44852079 |
| 10 | 97850481 |
| 11 | 137599280 |
| 12 | 1855038645 |
| 13 | 100034487540 |
| 14 | 879190467169 |
| 15 | 1918065106671 |
| 16 | 2697221086300 |
| 17 | 36362467421275 |
| 18 | 1960876019662560 |
| 19 | 17233891492577759 |
| 20 | 37597912123131361 |