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 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 18 |
| 5 | 54 |
| 6 | 156 |
| 7 | 412 |
| 8 | 1168 |
| 9 | 3200 |
| 10 | 8848 |
| 11 | 24192 |
| 12 | 66632 |
| 13 | 181912 |
| 14 | 495536 |
| 15 | 1354880 |
| 16 | 3680352 |
| 17 | 9997056 |
| 18 | 27093216 |
| 19 | 73376512 |
| 20 | 198355840 |
| 21 | 535319168 |
| 22 | 1443042688 |
| 23 | 3884515008 |
| 24 | 10445579840 |
| 25 | 28046885824 |
| 26 | 75225974912 |
| 27 | 201536064896 |
| 28 | 539339293824 |
| 29 | 1441781213952 |