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 | 0 |
| 2 | 127 |
| 3 | 2186 |
| 4 | 16383 |
| 5 | 78124 |
| 6 | 279935 |
| 7 | 823542 |
| 8 | 2097151 |
| 9 | 4782968 |
| 10 | 9999999 |
| 11 | 19487170 |
| 12 | 35831807 |
| 13 | 62748516 |
| 14 | 105413503 |
| 15 | 170859374 |
| 16 | 268435455 |
| 17 | 410338672 |
| 18 | 612220031 |
| 19 | 893871738 |
| 20 | 1279999999 |
| 21 | 1801088540 |
| 22 | 2494357887 |
| 23 | 3404825446 |
| 24 | 4586471423 |
| 25 | 6103515624 |
| 26 | 8031810175 |