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 | 75 |
| 2 | 315 |
| 3 | 1275 |
| 4 | 5115 |
| 5 | 19275 |
| 6 | 20475 |
| 7 | 76875 |
| 8 | 81915 |
| 9 | 307275 |
| 10 | 322875 |
| 11 | 327675 |
| 12 | 1228875 |
| 13 | 1290555 |
| 14 | 1310715 |
| 15 | 4915275 |
| 16 | 4934475 |
| 17 | 5161275 |
| 18 | 5223675 |
| 19 | 5242875 |
| 20 | 19660875 |
| 21 | 19741515 |
| 22 | 20644155 |
| 23 | 20890875 |
| 24 | 20971515 |
| 25 | 78643275 |
| 26 | 78720075 |
| 27 | 78969675 |
| 28 | 82575675 |
| 29 | 82652475 |
| 30 | 83559675 |