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A262519 Odd bisection of A155043.

%I A262519 #9 Aug 31 2017 11:35:38
%S A262519 1,2,3,4,3,4,5,5,6,7,7,8,6,9,10,11,11,12,13,13,14,15,14,15,10,16,17,
%T A262519 17,18,19,20,19,21,22,22,23,24,23,25,26,15,16,16,17,18,18,19,19,20,20,
%U A262519 21,22,21,22,23,23,24,24,24,25,21,26,22,23,23,24,24,24,25,26,26,27,27,27,28,29,28,30,31,31,32,33,32,33,28,33,34,29,35,36,37,37
%N A262519 Odd bisection of A155043.
%C A262519 Number of steps needed to reach zero when starting from k = 2*n + 1 and repeatedly applying the map that replaces k by k - d(k), where d(k) is the number of divisors of k (A000005).
%H A262519 Antti Karttunen, <a href="/A262519/b262519.txt">Table of n, a(n) for n = 0..10000</a>
%H A262519 A. Karttunen, <a href="https://oeis.org/plot2a?name1=A262519&amp;name2=A262518&amp;tform1=untransformed&amp;tform2=untransformed&amp;shift=0&amp;radiop1=ratio&amp;drawlines=true">Ratio a(n)/A262518(n) drawn with the help of OEIS Plot2-script</a>
%F A262519 a(n) = A155043(2*n + 1).
%t A262519 Table[Length[NestWhileList[#-DivisorSigma[0,#]&,n,#!=0&]]-1,{n,1,200,2}] (* _Harvey P. Dale_, Aug 31 2017 *)
%o A262519 (Scheme) (define (A262519 n) (A155043 (+ n n 1)))
%Y A262519 Cf. A000005, A049820, A155043, A262518, A262520, A262521, A262681.
%K A262519 nonn
%O A262519 0,2
%A A262519 _Antti Karttunen_, Oct 02 2015