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 | 9 |
| 2 | 73 |
| 3 | 536 |
| 4 | 3590 |
| 5 | 22162 |
| 6 | 127604 |
| 7 | 693552 |
| 8 | 3598120 |
| 9 | 17990600 |
| 10 | 87396728 |
| 11 | 413977192 |
| 12 | 1918222840 |
| 13 | 8719846960 |
| 14 | 38983643908 |
| 15 | 171764779170 |
| 16 | 747190081890 |
| 17 | 3213760467348 |
| 18 | 13684132415133 |
| 19 | 57742830924831 |
| 20 | 241687792906641 |