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 | 1 |
| 3 | 2 |
| 4 | 9 |
| 5 | 28 |
| 6 | 66 |
| 7 | 153 |
| 8 | 433 |
| 9 | 1345 |
| 10 | 3952 |
| 11 | 10991 |
| 12 | 30954 |
| 13 | 90988 |
| 14 | 271845 |
| 15 | 804153 |
| 16 | 2361457 |
| 17 | 6979690 |
| 18 | 20842285 |
| 19 | 62493914 |
| 20 | 187274712 |
| 21 | 561448399 |
| 22 | 1688263179 |
| 23 | 5093148285 |
| 24 | 15393417178 |
| 25 | 46570446829 |
| 26 | 141063389488 |
| 27 | 427979185898 |
| 28 | 1300470246165 |
| 29 | 3956367018001 |
| 30 | 12048354848013 |
| 31 | 36728336040306 |