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 | 15 |
| 3 | 169 |
| 4 | 1695 |
| 5 | 15961 |
| 6 | 144495 |
| 7 | 1273609 |
| 8 | 11012415 |
| 9 | 93864121 |
| 10 | 791266575 |
| 11 | 6612607849 |
| 12 | 54878189535 |
| 13 | 452866803481 |
| 14 | 3719823438255 |
| 15 | 30436810578889 |
| 16 | 248242046141055 |
| 17 | 2019169299698041 |
| 18 | 16385984911571535 |
| 19 | 132716292890482729 |
| 20 | 1073129238309234975 |
| 21 | 8664826172771491801 |