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 | 191 |
| 3 | 2551 |
| 4 | 18813 |
| 5 | 94967 |
| 6 | 397627 |
| 7 | 1647135 |
| 8 | 7862009 |
| 9 | 45136639 |
| 10 | 292475319 |
| 11 | 1996813991 |
| 12 | 13877119093 |
| 13 | 96951759015 |
| 14 | 678328486451 |
| 15 | 4747732369423 |
| 16 | 33233199005169 |
| 17 | 232630924325999 |
| 18 | 1628414210130607 |
| 19 | 11398896079245015 |
| 20 | 79792267577612141 |
| 21 | 558545865884372695 |