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 | 3 |
| 2 | 7 |
| 3 | 18 |
| 4 | 48 |
| 5 | 124 |
| 6 | 324 |
| 7 | 850 |
| 8 | 2226 |
| 9 | 5832 |
| 10 | 15285 |
| 11 | 40056 |
| 12 | 104976 |
| 13 | 275115 |
| 14 | 721006 |
| 15 | 1889568 |
| 16 | 4952070 |
| 17 | 12978093 |
| 18 | 34012224 |
| 19 | 89137244 |
| 20 | 233605664 |
| 21 | 612220032 |
| 22 | 1604470381 |
| 23 | 4204901942 |
| 24 | 11019960576 |
| 25 | 28880466845 |
| 26 | 75688234943 |
| 27 | 198359290368 |
| 28 | 519848403194 |