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 | 23 |
| 2 | 181 |
| 3 | 1457 |
| 4 | 11953 |
| 5 | 99593 |
| 6 | 840241 |
| 7 | 7160057 |
| 8 | 61503553 |
| 9 | 531715913 |
| 10 | 4620992401 |
| 11 | 40333791257 |
| 12 | 353325795553 |
| 13 | 3104682336233 |
| 14 | 27353203130161 |
| 15 | 241545689168057 |
| 16 | 2137316275469953 |
| 17 | 18945908172796553 |
| 18 | 168210593763149521 |