%I A132404
%S A132404 3,20,60,204,1,420,660,2040
%V A132404 3,20,60,204,-1,420,660,2040
%N A132404 Smallest short legs 'A' of exactly n primitive Pythagorean triangles, 
               or -1 if no such shortest leg exists.
%e A132404 1, 3.4.5
%e A132404 2, 20.21.29, 20.99.101
%e A132404 3, 60.91.109, 60.221.229, 60.899.901
%e A132404 4, 204.253.325, 204.1147.1165, 204.2597.2605, 204.10403.10405
%e A132404 5, -1 -- No numbers can represent short legs 'A' of exactly 5 primitive 
               Pythagorean triangles.
%e A132404 6, 420.851.949, 420.1189.1261, 420.1739.1789, 420.4891.4909, 420.11021.11029, 
               420.44099.44101
%e A132404 7, 660.779.1021, 660.989.1189, 660.2989.3061, 660.4331.4381, 660.12091.12109, 
               660.27221.27229, 660.108899.108901
%t A132404 PyphagoreanAs[a_]:=(q={};k=0;If[a>=8,r=4,r=1];Do[y=(a^2+b^2)^0.5;c=IntegerPart[y];
               If[c==y,p=0;If[GCD[a,b,c]==1,AppendTo[q,a.b.c];k++ ]],{b,a+1,a^2/
               r}];PrependTo[q,k];q)lst={};x=0;Do[w=PyphagoreanAs[n][[1]];If[w>x,
               Print[Date[],"A=",n,",w=",w];AppendTo[lst,n];x=w],{n,7!}];lst
%Y A132404 Sequence in context: A002461 A031106 A143582 this_sequence A062359 A099721 
               A024402
%Y A132404 Adjacent sequences: A132401 A132402 A132403 this_sequence A132405 A132406 
               A132407
%K A132404 sign
%O A132404 1,1
%A A132404 Vladimir Orlovsky (4vladimir(AT)gmail.com), Aug 26 2008