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 | 15 |
| 2 | 77 |
| 3 | 405 |
| 4 | 2177 |
| 5 | 11925 |
| 6 | 66377 |
| 7 | 374445 |
| 8 | 2135777 |
| 9 | 12292965 |
| 10 | 71280377 |
| 11 | 415819485 |
| 12 | 2437700177 |
| 13 | 14348506005 |
| 14 | 84736115177 |
| 15 | 501776304525 |
| 16 | 2977992765377 |
| 17 | 17706778767045 |
| 18 | 105443373410777 |
| 19 | 628708104245565 |