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 | 8 |
| 3 | 34 |
| 4 | 156 |
| 5 | 815 |
| 6 | 4946 |
| 7 | 34706 |
| 8 | 277768 |
| 9 | 2500077 |
| 10 | 25000990 |
| 11 | 275011176 |
| 12 | 3300134476 |
| 13 | 42901748643 |
| 14 | 600624481562 |
| 15 | 9009367224110 |
| 16 | 144149875586576 |
| 17 | 2450547884972761 |
| 18 | 44109861929510838 |
| 19 | 838087376660707252 |
| 20 | 16761747533214146580 |
| 21 | 351996698197497079951 |