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 | 7 |
| 3 | 49 |
| 4 | 392 |
| 5 | 3087 |
| 6 | 24353 |
| 7 | 192080 |
| 8 | 1515031 |
| 9 | 11949777 |
| 10 | 94253656 |
| 11 | 743424031 |
| 12 | 5863743809 |
| 13 | 46250174880 |
| 14 | 364797430823 |
| 15 | 2877333239921 |
| 16 | 22694914695208 |
| 17 | 179005735545903 |
| 18 | 1411904551687777 |
| 19 | 11136372010635760 |
| 20 | 87837935936264759 |