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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 8 |
| 5 | 20 |
| 6 | 44 |
| 7 | 140 |
| 8 | 320 |
| 9 | 476 |
| 10 | 3584 |
| 11 | 12311 |
| 12 | 4604 |
| 13 | 74879 |
| 14 | 414119 |
| 15 | 2071775 |
| 16 | 5703551 |
| 17 | 11551671 |
| 18 | 45680444 |
| 19 | 442548224 |
| 20 | 1960632176 |
| 21 | 2657058876 |
| 22 | 24923993276 |
| 23 | 130518272975 |
| 24 | 1478154932316 |
| 25 | 5446454455004 |
| 26 | 38610655379975 |