%I #2 Mar 30 2012 17:28:33

%S 4,15,21,35,55,77,91,99,117,143,153,171,187,209,221,247,253,299,323,

%T 325,377,391,403,425,437,475,493,527,551,575,589,621,629,667,697,703,

%U 713,725,775,779,783,817,837,851,899,925,943,957,989,999,1023,1025,1073

%N Long legs of Pythagorean triangles that are not divisible by any other long leg of a Pythagorean triangle.

%C All long legs of Pythagorean triangles (A009023) are multiples of these values, so these values can be thought of as "primes" of the sequence of long legs.

%o (PARI) llp = vector(60); np = 1; llp[np] = 4;

%o notdiv(k) = for(j=1,np,if(k%llp[j],1,return(0)));return(1);

%o isLongLeg(n) = local(b);b=0;for(k=1,n-1,if(issquare(k^2+n^2),b=1));return(b);

%o for(k=4,1175,if(notdiv(k),if(isLongLeg(k),np+=1;llp[np]=k)))

%o for(n=1,60,print1(llp[n],", "))

%Y A009023

%K nonn

%O 1,1

%A _Gerald McGarvey_, Nov 01 2009

%E Comments and PARI program corrected by _Gerald McGarvey_, Nov 03 2009