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 | 150 |
| 2 | 486 |
| 3 | 1597 |
| 4 | 5211 |
| 5 | 16649 |
| 6 | 53553 |
| 7 | 172980 |
| 8 | 558743 |
| 9 | 1801720 |
| 10 | 5808944 |
| 11 | 18737526 |
| 12 | 60447764 |
| 13 | 194984049 |
| 14 | 628912080 |
| 15 | 2028584905 |
| 16 | 6543438398 |
| 17 | 21106550023 |
| 18 | 68080857417 |
| 19 | 219600230083 |
| 20 | 708339701336 |
| 21 | 2284812500323 |
| 22 | 7369860423165 |