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 | 3 |
| 1 | 3 |
| 2 | 9 |
| 3 | 24 |
| 4 | 69 |
| 5 | 198 |
| 6 | 570 |
| 7 | 1641 |
| 8 | 4725 |
| 9 | 13605 |
| 10 | 39174 |
| 11 | 112797 |
| 12 | 324786 |
| 13 | 935184 |
| 14 | 2692755 |
| 15 | 7753479 |
| 16 | 22325253 |
| 17 | 64283004 |
| 18 | 185095533 |
| 19 | 532961346 |
| 20 | 1534601034 |
| 21 | 4418707569 |
| 22 | 12723161361 |
| 23 | 36634883049 |
| 24 | 105485941578 |
| 25 | 303734663373 |
| 26 | 874569107070 |
| 27 | 2518221379632 |
| 28 | 7250929475523 |