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 | 13 |
| 3 | 103 |
| 4 | 869 |
| 5 | 7476 |
| 6 | 65323 |
| 7 | 577242 |
| 8 | 5144949 |
| 9 | 46167196 |
| 10 | 416527828 |
| 11 | 3774785983 |
| 12 | 34336862435 |
| 13 | 313330665532 |
| 14 | 2866982877954 |
| 15 | 26294890918308 |
| 16 | 241665561294741 |
| 17 | 2225104901535564 |
| 18 | 20520648006149980 |
| 19 | 189523353219338572 |
| 20 | 1752680220372189364 |
| 21 | 16227703263403842768 |