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 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 20 |
| 6 | 71 |
| 7 | 259 |
| 8 | 961 |
| 9 | 3606 |
| 10 | 13640 |
| 11 | 51909 |
| 12 | 198497 |
| 13 | 762007 |
| 14 | 2934764 |
| 15 | 11333950 |
| 16 | 43874857 |
| 17 | 170193528 |
| 18 | 661386105 |
| 19 | 2574320659 |
| 20 | 10034398370 |
| 21 | 39163212165 |
| 22 | 153027659730 |
| 23 | 598577118991 |
| 24 | 2343628878849 |
| 25 | 9184197395425 |
| 26 | 36020235035016 |
| 27 | 141376666307608 |