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) |
|---|---|
| 1 | 4 |
| 2 | 43 |
| 3 | 231 |
| 4 | 1421 |
| 5 | 9033 |
| 6 | 55706 |
| 7 | 346032 |
| 8 | 2151932 |
| 9 | 13364992 |
| 10 | 83036263 |
| 11 | 515911384 |
| 12 | 3205231551 |
| 13 | 19913717003 |
| 14 | 123721335945 |
| 15 | 768662962676 |
| 16 | 4775598530205 |
| 17 | 29670139081754 |
| 18 | 184336490377417 |
| 19 | 1145257318539730 |
| 20 | 7115326466070793 |