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 | 3 |
| 3 | 21 |
| 4 | 65 |
| 5 | 393 |
| 6 | 5907 |
| 7 | 17731 |
| 8 | 372411 |
| 9 | 2234571 |
| 10 | 20111419 |
| 11 | 20111503 |
| 12 | 663680439 |
| 13 | 1991042087 |
| 14 | 77650650633 |
| 15 | 33278851497 |
| 16 | 19967311127 |
| 17 | 119803867191 |
| 18 | 6109997233605 |
| 19 | 54989975121893 |
| 20 | 1044809527432655 |
| 21 | 15672142912044093 |