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 | 2 |
| 3 | 5 |
| 4 | 32 |
| 5 | 133 |
| 6 | 636 |
| 7 | 2856 |
| 8 | 13169 |
| 9 | 60120 |
| 10 | 275632 |
| 11 | 1261451 |
| 12 | 5777107 |
| 13 | 26449970 |
| 14 | 121113272 |
| 15 | 554546205 |
| 16 | 2539172736 |
| 17 | 11626346343 |
| 18 | 53234805475 |
| 19 | 243751618738 |
| 20 | 1116090939600 |
| 21 | 5110360772166 |
| 22 | 23399338403512 |
| 23 | 107140971422686 |