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 | 1 |
| 2 | 3 |
| 3 | 13 |
| 4 | 19 |
| 5 | 41 |
| 6 | 99 |
| 7 | 197 |
| 8 | 419 |
| 9 | 913 |
| 10 | 1923 |
| 11 | 4093 |
| 12 | 8755 |
| 13 | 18617 |
| 14 | 39651 |
| 15 | 84533 |
| 16 | 180035 |
| 17 | 383521 |
| 18 | 817155 |
| 19 | 1740781 |
| 20 | 3708499 |
| 21 | 7900745 |
| 22 | 16831587 |
| 23 | 35857829 |
| 24 | 76391651 |
| 25 | 162744241 |
| 26 | 346709379 |
| 27 | 738628573 |
| 28 | 1573570675 |
| 29 | 3352327385 |
| 30 | 7141783779 |