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 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 26 |
| 5 | 74 |
| 6 | 208 |
| 7 | 586 |
| 8 | 1647 |
| 9 | 4646 |
| 10 | 13135 |
| 11 | 37247 |
| 12 | 105896 |
| 13 | 301880 |
| 14 | 862498 |
| 15 | 2469480 |
| 16 | 7083690 |
| 17 | 20353886 |
| 18 | 58571805 |
| 19 | 168780848 |
| 20 | 486958481 |
| 21 | 1406524978 |
| 22 | 4066735979 |
| 23 | 11769294050 |
| 24 | 34090034328 |
| 25 | 98820719105 |
| 26 | 286672555274 |