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 | 2 |
| 2 | 11 |
| 3 | 66 |
| 4 | 461 |
| 5 | 3448 |
| 6 | 27061 |
| 7 | 219702 |
| 8 | 1829851 |
| 9 | 15547142 |
| 10 | 134224361 |
| 11 | 1174119120 |
| 12 | 10383783641 |
| 13 | 92691197962 |
| 14 | 834047700091 |
| 15 | 7557110252538 |
| 16 | 68890745834341 |
| 17 | 631392034936040 |
| 18 | 5814520777199261 |
| 19 | 53776065007163886 |
| 20 | 499275423496447211 |