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 | 3 |
| 2 | 12 |
| 3 | 54 |
| 4 | 210 |
| 5 | 798 |
| 6 | 2850 |
| 7 | 10038 |
| 8 | 34410 |
| 9 | 116406 |
| 10 | 388362 |
| 11 | 1283430 |
| 12 | 4203786 |
| 13 | 13675038 |
| 14 | 44211570 |
| 15 | 142202574 |
| 16 | 455299242 |
| 17 | 1451997726 |
| 18 | 4614253122 |
| 19 | 14617620726 |
| 20 | 46177325994 |
| 21 | 145505603694 |
| 22 | 457437342546 |
| 23 | 1435074324006 |
| 24 | 4493508791754 |
| 25 | 14045385985902 |