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 | 0 |
| 3 | 0 |
| 4 | 170 |
| 5 | 13384 |
| 6 | 257318 |
| 7 | 2774728 |
| 8 | 20202298 |
| 9 | 110018552 |
| 10 | 481719518 |
| 11 | 1781124856 |
| 12 | 5756568738 |
| 13 | 16676946372 |
| 14 | 44127887910 |
| 15 | 108192675468 |
| 16 | 248568720338 |
| 17 | 539925974784 |
| 18 | 1116836380926 |
| 19 | 2212958151968 |
| 20 | 4220919779218 |