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 | 1 |
| 2 | 9 |
| 3 | 36 |
| 4 | 108 |
| 5 | 449 |
| 6 | 1212 |
| 7 | 4499 |
| 8 | 10914 |
| 9 | 43286 |
| 10 | 103296 |
| 11 | 306994 |
| 12 | 867763 |
| 13 | 2165484 |
| 14 | 6627800 |
| 15 | 16827227 |
| 16 | 42203212 |
| 17 | 104397436 |
| 18 | 282967414 |
| 19 | 632194758 |
| 20 | 1809241372 |
| 21 | 4120266946 |
| 22 | 10256452121 |
| 23 | 23140530512 |
| 24 | 55030272918 |
| 25 | 130803096050 |
| 26 | 291295024121 |
| 27 | 739011803928 |
| 28 | 1634625423738 |