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 | 2 |
| 1 | 2 |
| 2 | 2 |
| 3 | 3 |
| 4 | 8 |
| 5 | 16 |
| 6 | 47 |
| 7 | 132 |
| 8 | 435 |
| 9 | 1445 |
| 10 | 5103 |
| 11 | 18259 |
| 12 | 66934 |
| 13 | 247826 |
| 14 | 928137 |
| 15 | 3500559 |
| 16 | 13290552 |
| 17 | 50712016 |
| 18 | 194358380 |
| 19 | 747624825 |
| 20 | 2885120934 |
| 21 | 11164896416 |
| 22 | 43313276948 |
| 23 | 168400053019 |
| 24 | 656028153120 |
| 25 | 2560227845391 |
| 26 | 10007858038797 |
| 27 | 39178672900385 |
| 28 | 153586295761270 |
| 29 | 602842558581537 |
| 30 | 2368994981198048 |