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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 13 |
| 5 | 40 |
| 6 | 119 |
| 7 | 348 |
| 8 | 1011 |
| 9 | 2928 |
| 10 | 8471 |
| 11 | 24516 |
| 12 | 71023 |
| 13 | 206024 |
| 14 | 598513 |
| 15 | 1741332 |
| 16 | 5073733 |
| 17 | 14804160 |
| 18 | 43252855 |
| 19 | 126526756 |
| 20 | 370551287 |
| 21 | 1086365336 |
| 22 | 3188090101 |
| 23 | 9364411252 |
| 24 | 27529374201 |
| 25 | 80993754352 |
| 26 | 238463467529 |
| 27 | 702563144252 |
| 28 | 2071200546129 |
| 29 | 6109619428824 |