editing
approved
Cf. A238247.
proposed
a(n) = (s(n)-1)/2, where s(n) = ) is the n-th number whose base -2 representation has exactly 5 runs.
reviewed
Vincenzo Librandi, <a href="/A043688/b043688.txt">Table of n, a(n) for n = 1..1000</a>
a(n) = A238247(n) - 1. - Reinhard Zumkeller, Feb 20 2014