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 | 12 |
| 4 | 45 |
| 5 | 180 |
| 6 | 708 |
| 7 | 2832 |
| 8 | 11283 |
| 9 | 45132 |
| 10 | 180348 |
| 11 | 721392 |
| 12 | 2884860 |
| 13 | 11539440 |
| 14 | 46154928 |
| 15 | 184619712 |
| 16 | 738467565 |
| 17 | 2953870260 |
| 18 | 11815435908 |
| 19 | 47261743632 |
| 20 | 189046794180 |
| 21 | 756187176720 |
| 22 | 3024747985488 |
| 23 | 12098991941952 |
| 24 | 48395964882948 |