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 | 0 |
| 1 | 1 |
| 2 | 4097 |
| 3 | 535538 |
| 4 | 17312754 |
| 5 | 261453379 |
| 6 | 2438235715 |
| 7 | 16279522916 |
| 8 | 84998999652 |
| 9 | 367428536133 |
| 10 | 1367428536133 |
| 11 | 4505856912854 |
| 12 | 13421957361110 |
| 13 | 36720042483591 |
| 14 | 93413954858887 |
| 15 | 223160292749512 |
| 16 | 504635269460168 |
| 17 | 1087257506689929 |
| 18 | 2244088888116105 |
| 19 | 4457403807182266 |