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 | 4 |
| 2 | 30 |
| 3 | 215 |
| 4 | 1729 |
| 5 | 15176 |
| 6 | 143814 |
| 7 | 1462995 |
| 8 | 15876410 |
| 9 | 182811992 |
| 10 | 2223580281 |
| 11 | 28458251185 |
| 12 | 381943459065 |
| 13 | 5359649816728 |
| 14 | 78430018675440 |
| 15 | 1194057733357517 |
| 16 | 18873870914263424 |
| 17 | 309154787519651284 |
| 18 | 5238840625331179517 |