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 | 1 |
| 2 | 3 |
| 3 | 13 |
| 4 | 87 |
| 5 | 761 |
| 6 | 8243 |
| 7 | 106037 |
| 8 | 1578671 |
| 9 | 26685361 |
| 10 | 504770859 |
| 11 | 10562259533 |
| 12 | 242216304839 |
| 13 | 6040459572681 |
| 14 | 162750100464643 |
| 15 | 4711225866217381 |
| 16 | 145818462291970911 |
| 17 | 4805369568409107809 |
| 18 | 167982555421167341147 |
| 19 | 6208589923091273031293 |
| 20 | 241898639921607255506039 |