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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 21 |
| 4 | 91 |
| 5 | 703 |
| 6 | 3081 |
| 7 | 23871 |
| 8 | 104653 |
| 9 | 810901 |
| 10 | 3555111 |
| 11 | 27546753 |
| 12 | 120769111 |
| 13 | 935778691 |
| 14 | 4102594653 |
| 15 | 31788928731 |
| 16 | 139367449081 |
| 17 | 1079887798153 |
| 18 | 4734390674091 |
| 19 | 36684396208461 |
| 20 | 160829915470003 |
| 21 | 1246189583289511 |
| 22 | 5463482735306001 |
| 23 | 42333761435634903 |