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 | 75 |
| 6 | 216 |
| 7 | 622 |
| 8 | 1791 |
| 9 | 5157 |
| 10 | 14849 |
| 11 | 42756 |
| 12 | 123111 |
| 13 | 354484 |
| 14 | 1020696 |
| 15 | 2938977 |
| 16 | 8462447 |
| 17 | 24366645 |
| 18 | 70160958 |
| 19 | 202020427 |
| 20 | 581694636 |
| 21 | 1674922950 |
| 22 | 4822748423 |
| 23 | 13886550633 |
| 24 | 39984728949 |
| 25 | 115131438424 |
| 26 | 331507764639 |
| 27 | 954538564968 |
| 28 | 2748484256480 |