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 | 2 |
| 3 | 6 |
| 4 | 16 |
| 5 | 44 |
| 6 | 134 |
| 7 | 414 |
| 8 | 1290 |
| 9 | 4102 |
| 10 | 13306 |
| 11 | 43718 |
| 12 | 145176 |
| 13 | 487384 |
| 14 | 1651154 |
| 15 | 5636702 |
| 16 | 19381392 |
| 17 | 67074420 |
| 18 | 233483430 |
| 19 | 817106622 |
| 20 | 2873589060 |
| 21 | 10151255976 |
| 22 | 36009769278 |
| 23 | 128231072994 |
| 24 | 458268615966 |
| 25 | 1643227382022 |
| 26 | 5910606009330 |
| 27 | 21322486928518 |
| 28 | 77132729929864 |