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 | 1 |
| 2 | 6 |
| 3 | 21 |
| 4 | 146 |
| 5 | 1101 |
| 6 | 10632 |
| 7 | 107062 |
| 8 | 1151802 |
| 9 | 12845442 |
| 10 | 147845706 |
| 11 | 1743640908 |
| 12 | 20988257544 |
| 13 | 256987965379 |
| 14 | 3192893716320 |
| 15 | 40171643847696 |
| 16 | 510997002280522 |
| 17 | 6563060603543658 |
| 18 | 85017387536789916 |
| 19 | 1109744672540225367 |
| 20 | 14585261039005676046 |