Goodstein sequence
= Goodstein sequence
{c}
{title2=$m_{s+1}=B_{s+2,s+3}(m_s)-1$}
Start at base two. At each nonzero step, change every base occurrence in the <hereditary base representation> to the next base and subtract one. Although the natural-number terms can grow, their <ordinal ranks of a Goodstein term> decrease strictly. Keep zero fixed once it is reached.