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 | 4 |
| 3 | 26 |
| 4 | 72 |
| 5 | 282 |
| 6 | 908 |
| 7 | 2832 |
| 8 | 8856 |
| 9 | 26750 |
| 10 | 80088 |
| 11 | 237190 |
| 12 | 695272 |
| 13 | 2024064 |
| 14 | 5853676 |
| 15 | 16835874 |
| 16 | 48194664 |
| 17 | 137385394 |
| 18 | 390201476 |
| 19 | 1104636144 |
| 20 | 3118021376 |
| 21 | 8778028806 |
| 22 | 24653647608 |
| 23 | 69091665822 |
| 24 | 193246772832 |
| 25 | 539525988960 |
| 26 | 1503796131028 |