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 | 2 |
| 2 | 3 |
| 3 | 12 |
| 4 | 61 |
| 5 | 340 |
| 6 | 2070 |
| 7 | 13178 |
| 8 | 87115 |
| 9 | 590720 |
| 10 | 4089214 |
| 11 | 28766442 |
| 12 | 205072330 |
| 13 | 1478149486 |
| 14 | 10754615963 |
| 15 | 78878136418 |
| 16 | 582563752101 |
| 17 | 4328922702536 |
| 18 | 32341244773080 |
| 19 | 242781826475456 |
| 20 | 1830377795460438 |