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 | -2 |
| 2 | -2 |
| 3 | 10 |
| 4 | 94 |
| 5 | 538 |
| 6 | 2638 |
| 7 | 12010 |
| 8 | 52414 |
| 9 | 222778 |
| 10 | 930478 |
| 11 | 3840010 |
| 12 | 15714334 |
| 13 | 63920218 |
| 14 | 258869518 |
| 15 | 1045044010 |
| 16 | 4208873854 |
| 17 | 16921588858 |
| 18 | 67944635758 |
| 19 | 272553384010 |
| 20 | 1092538058974 |
| 21 | 4377125804698 |
| 22 | 17529423925198 |
| 23 | 70180457820010 |
| 24 | 280910117637694 |
| 25 | 1124205329623738 |
| 26 | 4498515895713838 |