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 | 0 |
| 2 | 2 |
| 3 | 5 |
| 4 | 16 |
| 5 | 49 |
| 6 | 151 |
| 7 | 465 |
| 8 | 1432 |
| 9 | 4410 |
| 10 | 13581 |
| 11 | 41824 |
| 12 | 128801 |
| 13 | 396655 |
| 14 | 1221537 |
| 15 | 3761840 |
| 16 | 11584946 |
| 17 | 35676949 |
| 18 | 109870576 |
| 19 | 338356945 |
| 20 | 1042002567 |
| 21 | 3208946545 |
| 22 | 9882257736 |
| 23 | 30433357674 |
| 24 | 93722435101 |
| 25 | 288627200960 |
| 26 | 888855064897 |
| 27 | 2737314167775 |
| 28 | 8429820731201 |
| 29 | 25960439030624 |