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) |
|---|---|
| 1 | 1 |
| 2 | 15 |
| 3 | 149 |
| 4 | 1173 |
| 5 | 7996 |
| 6 | 49210 |
| 7 | 280751 |
| 8 | 1510267 |
| 9 | 7752966 |
| 10 | 38313584 |
| 11 | 183476493 |
| 12 | 855810005 |
| 13 | 3904023943 |
| 14 | 17474944971 |
| 15 | 76959615336 |
| 16 | 334220597220 |
| 17 | 1434013918092 |
| 18 | 6088757186340 |
| 19 | 25619291046722 |
| 20 | 106954200571650 |
| 21 | 443491592171780 |