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 | 4 |
| 3 | 16 |
| 4 | 59 |
| 5 | 214 |
| 6 | 768 |
| 7 | 2745 |
| 8 | 9792 |
| 9 | 34900 |
| 10 | 124339 |
| 11 | 442906 |
| 12 | 1577540 |
| 13 | 5618665 |
| 14 | 20011452 |
| 15 | 71272296 |
| 16 | 253840779 |
| 17 | 904068526 |
| 18 | 3219889720 |
| 19 | 11467810393 |
| 20 | 40843217384 |
| 21 | 145465283884 |
| 22 | 518082304131 |
| 23 | 1845177508818 |
| 24 | 6571697181084 |
| 25 | 23405446635913 |
| 26 | 83359734391300 |
| 27 | 296890096642144 |