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) |
|---|---|
| 3 | 1 |
| 4 | 4 |
| 5 | 12 |
| 6 | 36 |
| 7 | 105 |
| 8 | 306 |
| 9 | 889 |
| 10 | 2584 |
| 11 | 7515 |
| 12 | 21880 |
| 13 | 63778 |
| 14 | 186132 |
| 15 | 543855 |
| 16 | 1590876 |
| 17 | 4658580 |
| 18 | 13655472 |
| 19 | 40065243 |
| 20 | 117654876 |
| 21 | 345786396 |
| 22 | 1017040380 |
| 23 | 2993498739 |
| 24 | 8816790906 |
| 25 | 25984489545 |
| 26 | 76625467128 |
| 27 | 226085062525 |
| 28 | 667415280376 |
| 29 | 1971209865654 |
| 30 | 5824651789852 |