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 | 3 |
| 2 | 5 |
| 3 | 17 |
| 4 | 49 |
| 5 | 161 |
| 6 | 513 |
| 7 | 1665 |
| 8 | 5377 |
| 9 | 17409 |
| 10 | 56321 |
| 11 | 182273 |
| 12 | 589825 |
| 13 | 1908737 |
| 14 | 6176769 |
| 15 | 19988481 |
| 16 | 64684033 |
| 17 | 209321985 |
| 18 | 677380097 |
| 19 | 2192048129 |
| 20 | 7093616641 |
| 21 | 22955425793 |
| 22 | 74285318145 |
| 23 | 240392339457 |
| 24 | 777925951489 |
| 25 | 2517421260801 |
| 26 | 8146546327553 |
| 27 | 26362777698305 |