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 | 4 |
| 2 | 12 |
| 3 | 36 |
| 4 | 100 |
| 5 | 284 |
| 6 | 780 |
| 7 | 2172 |
| 8 | 5916 |
| 9 | 16268 |
| 10 | 44100 |
| 11 | 120292 |
| 12 | 324932 |
| 13 | 881500 |
| 14 | 2374444 |
| 15 | 6416596 |
| 16 | 17245332 |
| 17 | 46466676 |
| 18 | 124658732 |
| 19 | 335116620 |
| 20 | 897697164 |
| 21 | 2408806028 |
| 22 | 6444560484 |
| 23 | 17266613812 |
| 24 | 46146397316 |
| 25 | 123481354908 |
| 26 | 329712786220 |
| 27 | 881317491628 |