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 | 1 |
| 2 | 7 |
| 3 | 9 |
| 4 | 177 |
| 5 | 2715 |
| 6 | 42975 |
| 7 | 91665 |
| 8 | 3493665 |
| 9 | 97345395 |
| 10 | 2601636975 |
| 11 | 70985324025 |
| 12 | 57891366225 |
| 13 | 9411029102475 |
| 14 | 476966861546175 |
| 15 | 20499289200014625 |
| 16 | 847876038362978625 |
| 17 | 35160445175104123875 |
| 18 | 1487419121780448231375 |
| 19 | 945654757149212735625 |
| 20 | 357657177058846280240625 |