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 | 6 |
| 2 | 56 |
| 3 | 486 |
| 4 | 4016 |
| 5 | 32526 |
| 6 | 261416 |
| 7 | 2094966 |
| 8 | 16770656 |
| 9 | 134198046 |
| 10 | 1073682776 |
| 11 | 8589757446 |
| 12 | 68718945296 |
| 13 | 549754219566 |
| 14 | 4398041728136 |
| 15 | 35184357739926 |
| 16 | 281474933663936 |
| 17 | 2251799684545086 |
| 18 | 18014398122061496 |
| 19 | 144115186913594406 |