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 | 3 |
| 2 | 10 |
| 3 | 36 |
| 4 | 135 |
| 5 | 519 |
| 6 | 2034 |
| 7 | 8100 |
| 8 | 32688 |
| 9 | 133380 |
| 10 | 549342 |
| 11 | 2280690 |
| 12 | 9534591 |
| 13 | 40103019 |
| 14 | 169583382 |
| 15 | 720549432 |
| 16 | 3074694552 |
| 17 | 13170845916 |
| 18 | 56616211818 |
| 19 | 244144402182 |
| 20 | 1055875341888 |
| 21 | 4578616787256 |
| 22 | 19903066450722 |
| 23 | 86713862341590 |