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 | 13 |
| 3 | 47 |
| 4 | 173 |
| 5 | 678 |
| 6 | 2735 |
| 7 | 11378 |
| 8 | 48279 |
| 9 | 208410 |
| 10 | 911571 |
| 11 | 4031919 |
| 12 | 17999628 |
| 13 | 81000573 |
| 14 | 367040404 |
| 15 | 1673295419 |
| 16 | 7669312343 |
| 17 | 35319197637 |
| 18 | 163350479756 |
| 19 | 758406642839 |
| 20 | 3533447414030 |
| 21 | 16514820417166 |
| 22 | 77412170863861 |