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 | 15 |
| 3 | 180 |
| 4 | 2001 |
| 5 | 20755 |
| 6 | 200082 |
| 7 | 1781941 |
| 8 | 14637962 |
| 9 | 111011667 |
| 10 | 779695050 |
| 11 | 5093379110 |
| 12 | 31092553357 |
| 13 | 178203364143 |
| 14 | 963217652830 |
| 15 | 4930357535218 |
| 16 | 23989343505296 |
| 17 | 111335037107474 |
| 18 | 494383391324356 |
| 19 | 2106346854756098 |