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 | 14 |
| 3 | 80 |
| 4 | 486 |
| 5 | 3030 |
| 6 | 19184 |
| 7 | 122924 |
| 8 | 794678 |
| 9 | 5173160 |
| 10 | 33863666 |
| 11 | 222683588 |
| 12 | 1469908848 |
| 13 | 9733916596 |
| 14 | 64636957300 |
| 15 | 430240178484 |
| 16 | 2869778018070 |
| 17 | 19177245746844 |
| 18 | 128361805431752 |
| 19 | 860443079597872 |
| 20 | 5775392952659170 |
| 21 | 38811408514848032 |
| 22 | 261101034656317244 |