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 | 0 |
| 2 | 12 |
| 3 | 30 |
| 4 | 144 |
| 5 | 536 |
| 6 | 2172 |
| 7 | 8544 |
| 8 | 33960 |
| 9 | 134480 |
| 10 | 533248 |
| 11 | 2113456 |
| 12 | 8377808 |
| 13 | 33207936 |
| 14 | 131632288 |
| 15 | 521770784 |
| 16 | 2068227136 |
| 17 | 8198158272 |
| 18 | 32496344448 |
| 19 | 128810916224 |
| 20 | 510588286464 |
| 21 | 2023899853184 |
| 22 | 8022453208832 |
| 23 | 31799871553536 |
| 24 | 126050200002816 |