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 | 6 |
| 2 | 45 |
| 3 | 378 |
| 4 | 3321 |
| 5 | 29646 |
| 6 | 266085 |
| 7 | 2392578 |
| 8 | 21526641 |
| 9 | 193720086 |
| 10 | 1743421725 |
| 11 | 15690618378 |
| 12 | 141215033961 |
| 13 | 1270933711326 |
| 14 | 11438398618965 |
| 15 | 102945573221778 |
| 16 | 926510115949281 |
| 17 | 8338590914403366 |
| 18 | 75047317842209805 |
| 19 | 675425859417626778 |