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 | 16 |
| 4 | 106 |
| 5 | 426 |
| 6 | 3076 |
| 7 | 15856 |
| 8 | 123516 |
| 9 | 757756 |
| 10 | 6315976 |
| 11 | 44203776 |
| 12 | 391582456 |
| 13 | 3043809016 |
| 14 | 28496668656 |
| 15 | 241563299776 |
| 16 | 2378813448976 |
| 17 | 21703877431056 |
| 18 | 223903020594016 |
| 19 | 2177251989389056 |
| 20 | 23448038945820576 |
| 21 | 241173237884726176 |