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A141346 Sum of the distinct digits of the prime factors of n. 1

%I

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

%T 4,10,12,5,10,12,4,7,5,12,7,3,8,5,11,5,7,7,11,6,8,5,6,9,13,11,14,10,7,

%U 6,10,2,9,6,13,10,5,14,8,5,10,12,8,12,8,6,16,7,3,7,11,12,13,9,14,3,17,10

%N Sum of the distinct digits of the prime factors of n.

%C Motivated by seeking an explanation for A080592. For n >= 2, 1 <= a(n) <= 45. For n >= 1, a(n) <= A095402(n).

%e a(44) = 3 as 44 = 2^2 * 11 and the sum of the distinct digits of the prime factors is 1 + 2 (whereas A095402(44) = 4 = 1 + 1 + 2).

%t Join[{0},Rest[Total[Union[Flatten[IntegerDigits/@Transpose[ FactorInteger[ #]][[1]]]]]&/@Range[90]]] (* _Harvey P. Dale_, Nov 30 2011 *)

%Y Cf. A095402, A080592, A008472.

%K base,nonn

%O 1,2

%A _Rick L. Shepherd_, Jun 26 2008

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Last modified September 20 04:38 EDT 2021. Contains 347577 sequences. (Running on oeis4.)