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 | 28 |
| 5 | 112 |
| 6 | 439 |
| 7 | 1711 |
| 8 | 6652 |
| 9 | 25846 |
| 10 | 100450 |
| 11 | 390670 |
| 12 | 1520764 |
| 13 | 5925718 |
| 14 | 23112931 |
| 15 | 90239407 |
| 16 | 352654084 |
| 17 | 1379410438 |
| 18 | 5400188206 |
| 19 | 21157958962 |
| 20 | 82959736504 |
| 21 | 325514137048 |
| 22 | 1278093308806 |
| 23 | 5021436970822 |
| 24 | 19740128055928 |