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 | 7 |
| 2 | 40 |
| 3 | 217 |
| 4 | 1159 |
| 5 | 6160 |
| 6 | 32689 |
| 7 | 173383 |
| 8 | 919480 |
| 9 | 4875913 |
| 10 | 25856071 |
| 11 | 137109280 |
| 12 | 727060321 |
| 13 | 3855438727 |
| 14 | 20444528200 |
| 15 | 108412748857 |
| 16 | 574888488199 |
| 17 | 3048504677680 |
| 18 | 16165536349969 |
| 19 | 85722212350663 |
| 20 | 454565659304920 |