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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 16 |
| 5 | 48 |
| 6 | 138 |
| 7 | 414 |
| 8 | 1226 |
| 9 | 3678 |
| 10 | 10986 |
| 11 | 32958 |
| 12 | 98736 |
| 13 | 296208 |
| 14 | 888210 |
| 15 | 2664630 |
| 16 | 7992664 |
| 17 | 23977992 |
| 18 | 71930298 |
| 19 | 215790894 |
| 20 | 647361696 |
| 21 | 1942085088 |
| 22 | 5826222306 |
| 23 | 17478666918 |
| 24 | 52435902018 |
| 25 | 157307706054 |
| 26 | 471922821954 |
| 27 | 1415768465862 |