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 | 2 |
| 2 | 10 |
| 3 | 50 |
| 4 | 266 |
| 5 | 1452 |
| 6 | 8074 |
| 7 | 45474 |
| 8 | 258570 |
| 9 | 1481108 |
| 10 | 8533660 |
| 11 | 49402850 |
| 12 | 287134346 |
| 13 | 1674425300 |
| 14 | 9792273690 |
| 15 | 57407789550 |
| 16 | 337281021450 |
| 17 | 1985342102964 |
| 18 | 11706001102180 |
| 19 | 69124774458092 |
| 20 | 408737856117916 |
| 21 | 2419833655003752 |
| 22 | 14341910428953018 |
| 23 | 85087759173024870 |