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 | 7 |
| 2 | 48 |
| 3 | 378 |
| 4 | 2539 |
| 5 | 17363 |
| 6 | 120124 |
| 7 | 830890 |
| 8 | 5746499 |
| 9 | 39745115 |
| 10 | 274872588 |
| 11 | 1900931060 |
| 12 | 13146313579 |
| 13 | 90916738809 |
| 14 | 628758673194 |
| 15 | 4348344850906 |
| 16 | 30072109222833 |
| 17 | 207971483025113 |
| 18 | 1438280832129012 |
| 19 | 9946804915649296 |
| 20 | 68789714754091787 |