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 | 3 |
| 2 | 6 |
| 3 | 45 |
| 4 | 126 |
| 5 | 750 |
| 6 | 2796 |
| 7 | 19389 |
| 8 | 75894 |
| 9 | 449562 |
| 10 | 2027796 |
| 11 | 12211794 |
| 12 | 57895596 |
| 13 | 332787324 |
| 14 | 1677545304 |
| 15 | 9766642077 |
| 16 | 50378641830 |
| 17 | 286825948194 |
| 18 | 1529968671492 |
| 19 | 8729259097158 |
| 20 | 47374697101572 |
| 21 | 269062276076868 |
| 22 | 1484430536591592 |