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 | 3 |
| 2 | 19 |
| 3 | 60 |
| 4 | 379 |
| 5 | 1197 |
| 6 | 7561 |
| 7 | 23880 |
| 8 | 150841 |
| 9 | 476403 |
| 10 | 3009259 |
| 11 | 9504180 |
| 12 | 60034339 |
| 13 | 189607197 |
| 14 | 1197677521 |
| 15 | 3782639760 |
| 16 | 23893516081 |
| 17 | 75463188003 |
| 18 | 476672644099 |
| 19 | 1505481120300 |
| 20 | 9509559365899 |
| 21 | 30034159217997 |