%I #13 Apr 19 2015 22:24:01
%S 0,1,1,2,2,3,3,4,4,5,6,5,6,7,7,8,8,9,10,9,10,11,12,11,13,14,12,13,14,
%T 15,15,16,16,17,18,17,18,19,20,19,21,22,20,21,22,23,24,23,25,26,24,25,
%U 27,28,26,29,30,27,28,29,30,31,31,32,32,33,34,33,34,35,36,35,37,38,36,37,38,39,40,39,41,42,40,41,43,44,42
%N If A079559(n) = 1, a(n) = A213714(n) - 1, otherwise a(n) = A234017(n).
%C In other words, if n = A005187(k) for some k >= 1, then a(n) = k-1, otherwise it must be that n = A055938(h) for some h, and then a(n) = h.
%C In binary trees like A233276 and A233278, a(n) gives the contents at the parent node of node containing n, for any n >= 1.
%C When iterating a(n), a(a(n)), a(a(a(n))), and so on, A070939(n) = A256478(n) + A256479(n) = A257248(n) + A257249(n) gives the number of steps needed to reach zero, from any starting value n >= 1.
%H Antti Karttunen, <a href="/A256991/b256991.txt">Table of n, a(n) for n = 1..16384</a>
%F If A079559(n) = 1, a(n) = A213714(n) - 1, otherwise a(n) = A234017(n).
%F a(n) = A256992(n) - A079559(n) = A213714(n) + A234017(n) - A079559(n).
%o (Scheme) (define (A256991 n) (if (not (zero? (A079559 n))) (+ -1 (A213714 n)) (A234017 n)))
%Y Cf. A005187, A055938, A079559, A213714, A234017.
%Y Cf. also A256992 (variant), A256478, A256479, A233276, A233278, A257248, A257249.
%K nonn
%O 1,4
%A _Antti Karttunen_, Apr 15 2015