OFFSET
1,2
COMMENTS
Using the law of cosines, the angle A opposite side a has cos A = (b^2 + c^2 - a^2) / (2bc) and the cosine uniquely identifies an angle of a triangle.
PROG
(PARI) A123325(n)=local(i, j, k, l); r=0; l=listcreate(n^3); for(i=1, n, for(j=1, n, for(k=1, n, if(gcd(i, gcd(j, k))==1&&2*max(i, max(j, k))<i+j+k, listput(l, (j^2+k^2-i^2)/(2*j*k)))))); listsort(l, 1); matsize(Vec(l))[2]
CROSSREFS
KEYWORD
nonn
AUTHOR
Franklin T. Adams-Watters, Sep 25 2006
STATUS
approved