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 | 3 |
| 2 | 9 |
| 3 | 54 |
| 4 | 243 |
| 5 | 1215 |
| 6 | 5832 |
| 7 | 28431 |
| 8 | 137781 |
| 9 | 669222 |
| 10 | 3247695 |
| 11 | 15766083 |
| 12 | 76527504 |
| 13 | 371477259 |
| 14 | 1803179313 |
| 15 | 8752833270 |
| 16 | 42487113627 |
| 17 | 206236840311 |
| 18 | 1001094543576 |
| 19 | 4859415193527 |
| 20 | 23588096472765 |
| 21 | 114499026160038 |
| 22 | 555789946734999 |
| 23 | 2697861075645339 |
| 24 | 13095692747551008 |
| 25 | 63567827923461075 |