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 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 19 |
| 5 | 47 |
| 6 | 127 |
| 7 | 330 |
| 8 | 889 |
| 9 | 2378 |
| 10 | 6450 |
| 11 | 17510 |
| 12 | 47907 |
| 13 | 131388 |
| 14 | 362081 |
| 15 | 1000665 |
| 16 | 2774857 |
| 17 | 7714695 |
| 18 | 21505455 |
| 19 | 60084062 |
| 20 | 168234804 |
| 21 | 471977022 |
| 22 | 1326558625 |
| 23 | 3734804268 |
| 24 | 10531738149 |
| 25 | 29742332548 |
| 26 | 84111212892 |
| 27 | 238176473946 |
| 28 | 675269414372 |
| 29 | 1916715819186 |