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 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 41 |
| 5 | 257 |
| 6 | 2209 |
| 7 | 27009 |
| 8 | 455553 |
| 9 | 10831873 |
| 10 | 360452609 |
| 11 | 16786663425 |
| 12 | 1102243190785 |
| 13 | 101146710556673 |
| 14 | 13109796072955905 |
| 15 | 2379217548538511361 |
| 16 | 609386444958743363585 |
| 17 | 219178211386515281412097 |
| 18 | 111098724276069341895720961 |
| 19 | 79284929294467154275606200321 |