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 | 13 |
| 2 | 48 |
| 3 | 176 |
| 4 | 580 |
| 5 | 1844 |
| 6 | 5667 |
| 7 | 17047 |
| 8 | 50404 |
| 9 | 147090 |
| 10 | 424686 |
| 11 | 1215528 |
| 12 | 3453733 |
| 13 | 9752641 |
| 14 | 27393240 |
| 15 | 76587284 |
| 16 | 213260152 |
| 17 | 591707612 |
| 18 | 1636514439 |
| 19 | 4513276555 |
| 20 | 12414985996 |
| 21 | 34071252918 |
| 22 | 93305816418 |
| 23 | 255027755856 |
| 24 | 695815086025 |
| 25 | 1895348847349 |
| 26 | 5154987856512 |
| 27 | 14000952578552 |