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 | 1 |
| 2 | 3 |
| 3 | 14 |
| 4 | 106 |
| 5 | 971 |
| 6 | 10616 |
| 7 | 123330 |
| 8 | 1557753 |
| 9 | 20543071 |
| 10 | 287087740 |
| 11 | 4168599808 |
| 12 | 63349129196 |
| 13 | 996257865899 |
| 14 | 16268585660692 |
| 15 | 273934662738565 |
| 16 | 4763228582494891 |
| 17 | 85139749375446911 |
| 18 | 1565168115090666500 |
| 19 | 29500470904432682460 |
| 20 | 570091884338189871500 |