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 | 15 |
| 4 | 63 |
| 5 | 231 |
| 6 | 405 |
| 7 | 495 |
| 8 | 1485 |
| 9 | 2475 |
| 10 | 4095 |
| 11 | 14175 |
| 12 | 21735 |
| 13 | 24255 |
| 14 | 31185 |
| 15 | 79695 |
| 16 | 190575 |
| 17 | 218295 |
| 18 | 239085 |
| 19 | 294525 |
| 20 | 904365 |
| 21 | 1276275 |
| 22 | 2789325 |
| 23 | 3586275 |
| 24 | 4937625 |
| 25 | 6912675 |
| 26 | 10072755 |
| 27 | 17342325 |
| 28 | 17972955 |
| 29 | 26801775 |
| 30 | 46621575 |
| 31 | 80405325 |
| 32 | 192567375 |
| 33 | 326351025 |
| 34 | 333107775 |
| 35 | 654729075 |