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 | 0 |
| 1 | 4 |
| 2 | 12 |
| 3 | 36 |
| 4 | 132 |
| 5 | 492 |
| 6 | 1932 |
| 7 | 7596 |
| 8 | 30252 |
| 9 | 120516 |
| 10 | 481572 |
| 11 | 1924356 |
| 12 | 7695492 |
| 13 | 30774372 |
| 14 | 123089892 |
| 15 | 492329316 |
| 16 | 1969287012 |
| 17 | 7877027532 |
| 18 | 31507989612 |
| 19 | 126031476876 |
| 20 | 504125425932 |
| 21 | 2016499779372 |
| 22 | 8065997193132 |
| 23 | 32263981077036 |
| 24 | 129055916612652 |
| 25 | 516223635676236 |