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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 76 |
| 6 | 280 |
| 7 | 1045 |
| 8 | 3937 |
| 9 | 14938 |
| 10 | 56993 |
| 11 | 218414 |
| 12 | 840090 |
| 13 | 3241153 |
| 14 | 12537263 |
| 15 | 48604755 |
| 16 | 188799962 |
| 17 | 734631798 |
| 18 | 2862843281 |
| 19 | 11171582151 |
| 20 | 43647688211 |
| 21 | 170720728344 |
| 22 | 668414462009 |
| 23 | 2619400928928 |
| 24 | 10273572796046 |
| 25 | 40325085206853 |
| 26 | 158393604268277 |