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 | 5 |
| 2 | 17 |
| 3 | 53 |
| 4 | 161 |
| 5 | 485 |
| 6 | 1433 |
| 7 | 4229 |
| 8 | 12425 |
| 9 | 36485 |
| 10 | 106673 |
| 11 | 311957 |
| 12 | 909953 |
| 13 | 2654501 |
| 14 | 7728401 |
| 15 | 22503053 |
| 16 | 65425505 |
| 17 | 190239989 |
| 18 | 552507641 |
| 19 | 1604779373 |
| 20 | 4656679889 |