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) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 21 |
| 6 | 121 |
| 7 | 421 |
| 8 | 1121 |
| 9 | 2521 |
| 10 | 6301 |
| 11 | 23101 |
| 12 | 99001 |
| 13 | 386101 |
| 14 | 1301301 |
| 15 | 3943941 |
| 16 | 11779041 |
| 17 | 38241841 |
| 18 | 136988041 |
| 19 | 504616441 |
| 20 | 1793870941 |
| 21 | 6061831441 |
| 22 | 19923689941 |
| 23 | 66139128441 |
| 24 | 227052188441 |
| 25 | 800641330721 |
| 26 | 2831644750221 |
| 27 | 9870443816221 |
| 28 | 33869987735221 |