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 | 2 |
| 3 | 6 |
| 4 | 18 |
| 5 | 58 |
| 6 | 174 |
| 7 | 546 |
| 8 | 1638 |
| 9 | 4986 |
| 10 | 14994 |
| 11 | 45214 |
| 12 | 135642 |
| 13 | 407838 |
| 14 | 1223514 |
| 15 | 3672726 |
| 16 | 11018874 |
| 17 | 33063498 |
| 18 | 99190494 |
| 19 | 297593514 |
| 20 | 892780542 |
| 21 | 2678403690 |
| 22 | 8035217622 |
| 23 | 24105833722 |
| 24 | 72317501166 |
| 25 | 216953071986 |
| 26 | 650859219322 |
| 27 | 1952579289318 |
| 28 | 5857737927786 |
| 29 | 17573218697070 |