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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 10 |
| 5 | 30 |
| 6 | 91 |
| 7 | 268 |
| 8 | 790 |
| 9 | 2308 |
| 10 | 6737 |
| 11 | 19609 |
| 12 | 57044 |
| 13 | 165796 |
| 14 | 481823 |
| 15 | 1400028 |
| 16 | 4068577 |
| 17 | 11825459 |
| 18 | 34380152 |
| 19 | 99981942 |
| 20 | 290854486 |
| 21 | 846397344 |
| 22 | 2463892294 |
| 23 | 7174933683 |
| 24 | 20900764811 |
| 25 | 60904875999 |
| 26 | 177535250815 |
| 27 | 517673673674 |
| 28 | 1509950058629 |
| 29 | 4405547856394 |
| 30 | 12857716906991 |