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 | 5 |
| 2 | 27 |
| 3 | 155 |
| 4 | 927 |
| 5 | 5675 |
| 6 | 35127 |
| 7 | 218195 |
| 8 | 1354527 |
| 9 | 8386715 |
| 10 | 51749127 |
| 11 | 318163235 |
| 12 | 1949418927 |
| 13 | 11907099755 |
| 14 | 72529083927 |
| 15 | 440741148275 |
| 16 | 2672816984127 |
| 17 | 16180899860795 |
| 18 | 97813978879527 |
| 19 | 590561131589315 |
| 20 | 3561890520050127 |