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 | 11 |
| 3 | 55 |
| 4 | 380 |
| 5 | 2319 |
| 6 | 15171 |
| 7 | 96139 |
| 8 | 619773 |
| 9 | 3962734 |
| 10 | 25445515 |
| 11 | 163048957 |
| 12 | 1045897075 |
| 13 | 6705473761 |
| 14 | 43001795070 |
| 15 | 275730928993 |
| 16 | 1768128097215 |
| 17 | 11337760387473 |
| 18 | 72702310606249 |
| 19 | 466192677008538 |
| 20 | 2989403530821497 |
| 21 | 19169143325987983 |
| 22 | 122919655766448729 |