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 | 5 |
| 2 | 33 |
| 3 | 248 |
| 4 | 2020 |
| 5 | 17325 |
| 6 | 153699 |
| 7 | 1395084 |
| 8 | 12868839 |
| 9 | 120127865 |
| 10 | 1131633217 |
| 11 | 10737438816 |
| 12 | 102480890512 |
| 13 | 982880111192 |
| 14 | 9465545374920 |
| 15 | 91479218990688 |
| 16 | 886803360846876 |
| 17 | 8619761335490460 |
| 18 | 83982810424366860 |
| 19 | 819973263265010400 |
| 20 | 8020986875021209320 |