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 | 5 |
| 3 | 12 |
| 4 | 36 |
| 5 | 113 |
| 6 | 372 |
| 7 | 1260 |
| 8 | 4369 |
| 9 | 15420 |
| 10 | 55188 |
| 11 | 199728 |
| 12 | 729444 |
| 13 | 2684354 |
| 14 | 9942053 |
| 15 | 37025580 |
| 16 | 138547332 |
| 17 | 520602096 |
| 18 | 1963413621 |
| 19 | 7429132620 |
| 20 | 28192605840 |
| 21 | 107269427100 |
| 22 | 409120605684 |
| 23 | 1563749870614 |
| 24 | 5988829291716 |
| 25 | 22977549119237 |
| 26 | 88305875046480 |
| 27 | 339894311499660 |