A063742 - OEIS

%I #12 Apr 08 2023 05:02:06

%S 0,1,2,3,4,5,6,7,8,9,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,27,

%T 28,29,30,31,32,33,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,51,53,

%U 54,55,56,57,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78

%N Cototients: numbers k such that x - phi(x) = k has at least one solution.

%C Numbers in range of A051853, the cototients. Complement of non-cototients, A005278 with respect to natural numbers A000027.

%H Amiram Eldar, <a href="/A063742/b063742.txt">Table of n, a(n) for n = 1..10000</a>

%e First missing numbers are: 10,26,34,50,52,... These missing values are collected in A005278.

%t Union[Table[w-EulerPhi[w], {w, 1, A}] taken for sufficiently large A.

%Y Cf. A000010, A005278, A051953, A083533, A083534, A083536.

%Y Analogous to A002202.

%K nonn

%O 1,3

%A _Labos Elemer_, Aug 13 2001, corrected May 20 2003

%E Edited by _N. J. A. Sloane_, Nov 17 2008 at the suggestion of R. J. Mathar