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 | 5 |
| 3 | 18 |
| 4 | 47 |
| 5 | 108 |
| 6 | 233 |
| 7 | 486 |
| 8 | 995 |
| 9 | 2016 |
| 10 | 4061 |
| 11 | 8154 |
| 12 | 16343 |
| 13 | 32724 |
| 14 | 65489 |
| 15 | 131022 |
| 16 | 262091 |
| 17 | 524232 |
| 18 | 1048517 |
| 19 | 2097090 |
| 20 | 4194239 |
| 21 | 8388540 |
| 22 | 16777145 |
| 23 | 33554358 |
| 24 | 67108787 |
| 25 | 134217648 |
| 26 | 268435373 |
| 27 | 536870826 |
| 28 | 1073741735 |
| 29 | 2147483556 |
| 30 | 4294967201 |
| 31 | 8589934494 |
| 32 | 17179869083 |
| 33 | 34359738264 |