cp's OEIS Frontend

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.

A103250 Numbers x, without duplication, in Pythagorean triples x,y,z where x,y,z are relatively prime composite numbers and y is a perfect square.

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%I A103250 #15 Nov 14 2019 17:55:29
%S A103250 30,40,120,130,160,270,272,312,350,360,480,510,520,640,738,750,888,
%T A103250 1000,1080,1088,1160,1170,1200,1218,1248,1342,1400,1440,1470,1920,
%U A103250 1960,2040,2080,2080,2210,2430,2448,2560,2590,2808,2952,2968,3000,3150,3240,3250
%N A103250 Numbers x, without duplication, in Pythagorean triples x,y,z where x,y,z are relatively prime composite numbers and y is a perfect square.
%C A103250 The case where x and y are both squares cannot occur.
%H A103250 MathForFun, <a href="http://groups.yahoo.com/group/mathforfun/message/9962">Pythagorean triples</a>
%H A103250 Chenglong Zou, Peter Otzen, Cino Hilliard, <a href="/A103246/a103246.txt">Pythagorean triplets</a>, digest of 6 messages in mathfun Yahoo group, Mar 19, 2005.
%e A103250 x=30, y=16, 30^2 + 16^2 = 34^2. 30 is the 1st entry in the list.
%o A103250 (PARI) pythtrisq(n) = { local(a,b,c=0,k,x,y,z,vy,wx,vx,j); w = vector(n*n+1); for(a=1,n, for(b=1,n, x=2*a*b; y=b^2-a^2; z=b^2+a^2; if(y > 0 & issquare(y), c++; w[c]=x; print(x","y","z) ) ) ); vx=vector(c); w=vecsort(w); for(j=1,n*n, if(w[j]>0, k++; vx[k]=w[j]; ) ); for(j=1,200, print1(vx[j]",") ) }
%K A103250 easy,nonn
%O A103250 1,1
%A A103250 _Cino Hilliard_, Mar 19 2005