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 | 10 |
| 2 | 100 |
| 3 | 390 |
| 4 | 1521 |
| 5 | 8151 |
| 6 | 43681 |
| 7 | 206910 |
| 8 | 980100 |
| 9 | 4863870 |
| 10 | 24137569 |
| 11 | 117661437 |
| 12 | 573554601 |
| 13 | 2815061256 |
| 14 | 13816591936 |
| 15 | 67635405320 |
| 16 | 331090914025 |
| 17 | 1622397552875 |
| 18 | 7950003180625 |
| 19 | 38941246190550 |
| 20 | 190744660149156 |
| 21 | 934456590661998 |