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 | 12 |
| 2 | 132 |
| 3 | 1452 |
| 4 | 15852 |
| 5 | 173052 |
| 6 | 1884972 |
| 7 | 20532252 |
| 8 | 223437852 |
| 9 | 2431526492 |
| 10 | 26447593812 |
| 11 | 287669976492 |
| 12 | 3128064123732 |
| 13 | 34013987172972 |
| 14 | 369792173040492 |
| 15 | 4020299656610636 |
| 16 | 43702216875039660 |
| 17 | 475060467524653980 |
| 18 | 5163624600479230260 |
| 19 | 56125562454502452780 |
| 20 | 610010748386503122684 |