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 | 6 |
| 2 | 18 |
| 3 | 68 |
| 4 | 246 |
| 5 | 948 |
| 6 | 3572 |
| 7 | 13896 |
| 8 | 53286 |
| 9 | 208452 |
| 10 | 807132 |
| 11 | 3169080 |
| 12 | 12346300 |
| 13 | 48602760 |
| 14 | 190150440 |
| 15 | 750018448 |
| 16 | 2943363078 |
| 17 | 11627329764 |
| 18 | 45736940364 |
| 19 | 180897649368 |
| 20 | 712881236052 |
| 21 | 2822389182104 |
| 22 | 11138924119512 |
| 23 | 44137230865392 |
| 24 | 174405194802524 |
| 25 | 691557285091176 |