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 | 1 |
| 1 | 15 |
| 2 | 93 |
| 3 | 471 |
| 4 | 2773 |
| 5 | 16585 |
| 6 | 101649 |
| 7 | 631513 |
| 8 | 3965717 |
| 9 | 25103901 |
| 10 | 159916563 |
| 11 | 1023792939 |
| 12 | 6580680769 |
| 13 | 42436151201 |
| 14 | 274373773501 |
| 15 | 1777776831901 |
| 16 | 11538964492821 |
| 17 | 75001583213817 |
| 18 | 488059829837697 |
| 19 | 3178929941530215 |