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Number of positive integers not exceeding n that are relatively prime to reverse(n).
0

%I #3 Feb 11 2014 19:05:29

%S 1,1,2,2,4,2,6,4,6,10,10,7,13,14,10,16,17,12,16,10,7,10,12,7,12,13,9,

%T 14,14,20,29,31,20,34,35,20,37,38,25,20,18,14,21,20,15,23,23,14,24,40,

%U 27,42,37,29,40,41,30,44,45,20,31,29,21,31,28,20,32,33,23,60,67,48,72

%N Number of positive integers not exceeding n that are relatively prime to reverse(n).

%e Among the positive integers not exceeding 12, the seven numbers 1,2,4,5,8,10,11 are relatively prime to reverse(12)=21. Hence a(12)=7.

%t r = {}; Do[ s = FromDigits[Reverse[IntegerDigits[n]]]; j = 0; For[i = 1, i <= n, i++, If[GCD[s, i] == 1, j++ ]]; r = Append[r, j], {n, 1, 10^2}]; r

%Y Cf. A000010.

%K base,nonn

%O 1,3

%A _Joseph L. Pe_, Jul 14 2002