A262518 - OEIS

%I #7 Oct 03 2015 08:43:14

%S 0,1,2,2,3,3,3,4,5,4,5,5,6,6,6,6,7,7,10,8,8,8,9,9,9,10,10,10,10,11,10,

%T 12,19,12,13,13,11,14,14,14,14,15,12,16,15,15,17,16,13,18,19,17,14,18,

%U 14,18,18,19,19,20,15,21,21,20,16,22,16,23,17,23,17,24,24,25,25,24,25,26,25,27,26,26,28,27,26,27,28,28,28,29,27,29,29

%N Even bisection of A155043.

%C Number of steps needed to reach zero when starting from k = 2*n and repeatedly applying the map that replaces k by k - d(k), where d(k) is the number of divisors of k (A000005).

%H Antti Karttunen, <a href="/A262518/b262518.txt">Table of n, a(n) for n = 0..10000</a>

%F a(n) = A155043(2*n).

%o (Scheme) (define (A262518 n) (A155043 (+ n n)))

%Y Cf. A000005, A049820, A155043, A262519, A262520, A262682.

%K nonn

%O 0,3

%A _Antti Karttunen_, Oct 02 2015