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.
{x=0} = -5. This is equivalent to the recurrence conjectured above by _R. J. Mathar's wiki page.
{x=0} = -5. This is equivalent to the recurrence conjectured above by _R. J. Mathar has authored 0 sequences.