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 | 2 |
| 2 | 9 |
| 3 | 56 |
| 4 | 457 |
| 5 | 4626 |
| 6 | 55969 |
| 7 | 788192 |
| 8 | 12667041 |
| 9 | 228794930 |
| 10 | 4588565641 |
| 11 | 101177239032 |
| 12 | 2432842302409 |
| 13 | 63355077101666 |
| 14 | 1776375001149057 |
| 15 | 53354605111573376 |
| 16 | 1709123738571497089 |
| 17 | 58163561716542474402 |
| 18 | 2095597345534100575561 |