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 | 5 |
| 2 | 22 |
| 3 | 98 |
| 4 | 451 |
| 5 | 2135 |
| 6 | 10312 |
| 7 | 50468 |
| 8 | 249061 |
| 9 | 1235465 |
| 10 | 6147802 |
| 11 | 30650438 |
| 12 | 152986471 |
| 13 | 764135195 |
| 14 | 3818284492 |
| 15 | 19084248008 |
| 16 | 95399716681 |
| 17 | 476934013325 |
| 18 | 2384476356382 |
| 19 | 11921800651178 |
| 20 | 59607259863691 |
| 21 | 298031069141855 |