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 | 3 |
| 2 | 13 |
| 3 | 67 |
| 4 | 375 |
| 5 | 2189 |
| 6 | 13089 |
| 7 | 79479 |
| 8 | 487833 |
| 9 | 3018355 |
| 10 | 18792303 |
| 11 | 117589689 |
| 12 | 738844719 |
| 13 | 4658460165 |
| 14 | 29458662005 |
| 15 | 186761788579 |
| 16 | 1186655988771 |
| 17 | 7554520173441 |
| 18 | 48176764031385 |
| 19 | 307706150625855 |
| 20 | 1968040844127793 |
| 21 | 12602972755261195 |
| 22 | 80798365998084795 |
| 23 | 518536437750443773 |