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 | 30 |
| 4 | 160 |
| 5 | 873 |
| 6 | 4851 |
| 7 | 27300 |
| 8 | 155115 |
| 9 | 887910 |
| 10 | 5112767 |
| 11 | 29582886 |
| 12 | 171857127 |
| 13 | 1001762125 |
| 14 | 5856231825 |
| 15 | 34320863160 |
| 16 | 201579530004 |
| 17 | 1186231850298 |
| 18 | 6992515244280 |
| 19 | 41281814341780 |
| 20 | 244049819182260 |
| 21 | 1444558452300909 |
| 22 | 8560106124666867 |
| 23 | 50777065370076660 |