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 | 4 |
| 2 | 15 |
| 3 | 55 |
| 4 | 202 |
| 5 | 754 |
| 6 | 2881 |
| 7 | 11281 |
| 8 | 45124 |
| 9 | 183412 |
| 10 | 753331 |
| 11 | 3111739 |
| 12 | 12879982 |
| 13 | 53291398 |
| 14 | 220074325 |
| 15 | 906337909 |
| 16 | 3721011016 |
| 17 | 15228417832 |
| 18 | 62133328423 |
| 19 | 252794939071 |
| 20 | 1025901734866 |
| 21 | 4153971603034 |
| 22 | 16786738847785 |
| 23 | 67722274817305 |
| 24 | 272813804258572 |