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 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 42 |
| 6 | 132 |
| 7 | 429 |
| 8 | 1429 |
| 9 | 4860 |
| 10 | 16775 |
| 11 | 58679 |
| 12 | 207428 |
| 13 | 739970 |
| 14 | 2660157 |
| 15 | 9627149 |
| 16 | 35043221 |
| 17 | 128207940 |
| 18 | 471160868 |
| 19 | 1738387703 |
| 20 | 6436639288 |
| 21 | 23908119163 |
| 22 | 89056620547 |
| 23 | 332583259981 |
| 24 | 1244920744009 |
| 25 | 4669782159158 |
| 26 | 17550211110693 |
| 27 | 66073189230521 |