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 | 5 |
| 3 | 19 |
| 4 | 69 |
| 5 | 341 |
| 6 | 1203 |
| 7 | 6336 |
| 8 | 22593 |
| 9 | 121483 |
| 10 | 438533 |
| 11 | 2381512 |
| 12 | 8677763 |
| 13 | 47419503 |
| 14 | 173984792 |
| 15 | 954961034 |
| 16 | 3522101709 |
| 17 | 19397198595 |
| 18 | 71831252031 |
| 19 | 396646918211 |
| 20 | 1473610012405 |
| 21 | 8154682794333 |
| 22 | 30376120747792 |
| 23 | 168394714422722 |
| 24 | 628648474795879 |
| 25 | 3490216221862041 |
| 26 | 13053833414221023 |
| 27 | 72566287730964469 |