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 | 14 |
| 3 | 60 |
| 4 | 297 |
| 5 | 1584 |
| 6 | 8868 |
| 7 | 51412 |
| 8 | 305964 |
| 9 | 1858308 |
| 10 | 11472152 |
| 11 | 71774548 |
| 12 | 454080514 |
| 13 | 2899959640 |
| 14 | 18670920458 |
| 15 | 121056521536 |
| 16 | 789733186076 |
| 17 | 5180002637472 |
| 18 | 34141018474400 |
| 19 | 225995779077324 |
| 20 | 1501809350268648 |
| 21 | 10015202238242356 |
| 22 | 67003372168525774 |