This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A123325 #3 Mar 30 2012 17:35:16 %S A123325 1,3,9,17,35,49,82,109,149,188,262,316,419,500,607,698,876,1004,1222, %T A123325 1383,1589,1782,2108,2318,2634,2914,3253,3564,4088,4411,5000,5392, %U A123325 5917,6410,6995,7468,8308,8926,9661,10268,11313,11976,13136,13951,14875 %N A123325 Number of distinct angles in all integer-sided triangles with all sides <= n. %C A123325 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. %o A123325 (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] %Y A123325 Cf. A123323, A123324. %K A123325 nonn %O A123325 1,2 %A A123325 _Franklin T. Adams-Watters_, Sep 25 2006