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 | 6 |
| 2 | 21 |
| 3 | 75 |
| 4 | 267 |
| 5 | 938 |
| 6 | 3283 |
| 7 | 11516 |
| 8 | 40399 |
| 9 | 141745 |
| 10 | 497298 |
| 11 | 1744684 |
| 12 | 6121152 |
| 13 | 21475315 |
| 14 | 75342932 |
| 15 | 264330011 |
| 16 | 927363850 |
| 17 | 3253519870 |
| 18 | 11414498822 |
| 19 | 40046099291 |
| 20 | 140495874086 |
| 21 | 492909198404 |
| 22 | 1729299730308 |
| 23 | 6066994825927 |
| 24 | 21285162746386 |