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) |
|---|---|
| 2 | 1 |
| 3 | 7 |
| 4 | 37 |
| 5 | 178 |
| 6 | 823 |
| 7 | 3737 |
| 8 | 16833 |
| 9 | 75608 |
| 10 | 339610 |
| 11 | 1527944 |
| 12 | 6892210 |
| 13 | 31186533 |
| 14 | 141598200 |
| 15 | 645186895 |
| 16 | 2950261555 |
| 17 | 13538266219 |
| 18 | 62338173865 |
| 19 | 287993085103 |
| 20 | 1334712682675 |
| 21 | 6204513729392 |
| 22 | 28925212243136 |
| 23 | 135216169757852 |
| 24 | 633722949713612 |