A362181 - OEIS

%I #9 Apr 11 2023 04:18:04

%S 0,0,1,0,2,1,2,1,3,1,3,2,3,3,2,2,3,3,4,3,3,3,3,3,4,4,3,3,4,5,4,5,4,5,

%T 3,4,4,5,3,5,3,5,5,5,4,6,4,6,4,6,2,7,4,6,4,6,3,7,3,5,4,6,3,8,2,6,6,7,

%U 4,8,4,6,6,7,3,9,4,7,4,5,5,9,6,9,4,7,3

%N Number of numbers k such that A323410(k) = n.

%C The offset is 2 since A323410(p) = 1 for all prime powers p (A246655).

%C a(0) = 1, since there is only one solution, x = 1, to A323410(x) = 0.

%H Amiram Eldar, <a href="/A362181/b362181.txt">Table of n, a(n) for n = 2..10000</a>

%F a(A362182(n)) = 0.

%F a(A362185(n)) = 1.

%F a(A362186(n)) = n.

%t ucototient[n_] := n - Times @@ (Power @@@ FactorInteger[n] - 1); ucototient[1] = 0; With[{max = 100}, ucot = Table[ucototient[n], {n, 1, max^2}]; Table[Length[Position[ucot, n]], {n, 2, max}] // Flatten]

%Y Row lengths of A362180.

%Y The unitary version of A063740.

%Y Cf. A246655, A323410, A362182 (positions of 0's), A362183 (indices of records), A362184, A362185 (positions of 1's), A362186.

%Y Similar sequences: A014197, A361967.

%K nonn

%O 2,5

%A _Amiram Eldar_, Apr 10 2023