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A259053 Number of triangles with sides pairwise relatively prime and one maximal side being n; permutations of sides are not considered distinct.

%I A259053 #19 Jun 29 2015 21:15:18
%S A259053 1,0,0,0,1,0,3,2,4,1,11,2,17,6,8,9,32,6,42,12,22,15,64,12,56,25,49,25,
%T A259053 107,12,124,51,64,45,86,27,180,59,91,45,225,30,250,81,96,87,302,55,
%U A259053 263,82
%N A259053 Number of triangles with sides pairwise relatively prime and one maximal side being n; permutations of sides are not considered distinct.
%H A259053 Charles R Greathouse IV, <a href="/A259053/b259053.txt">Table of n, a(n) for n = 1..10000</a>
%t A259053 triangles[n_] := Module[{count = 0},
%t A259053    For[a = 1, a <= n, a++,
%t A259053     For[b = a, b <= n, b++,
%t A259053      If[(a + b > n) && CoprimeQ[a, b, n], count++]]];
%t A259053    count];
%t A259053 triangles[#] & /@ Range[50]
%o A259053 (PARI) a(n)=if(n==1, return(1)); sum(a=3,n-2, if(gcd(a,n)==1, my(an=a*n); sum(b=max(a+1,n-a+1), n-1, gcd(an, b)==1))) \\ _Charles R Greathouse IV_, Jun 29 2015
%Y A259053 First differences of A259446.
%K A259053 nonn
%O A259053 1,7
%A A259053 _Vincent J. Matsko_, Jun 29 2015