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.

A103251 Numbers x, without duplication, in Pythagorean triples x,y,z where x,y,z are relatively prime composite numbers and z is a perfect square.

Original entry on oeis.org

24, 96, 120, 216, 240, 336, 384, 480, 600, 720, 840, 840, 864, 960, 1080, 1176, 1320, 1344, 1536, 1920, 1944, 2016, 2160, 2184, 2400, 2520, 2880, 2904, 3000, 3024, 3360, 3360, 3360, 3456, 3696, 3840, 3960, 4056, 4320, 4704, 4896, 5280, 5280, 5376, 5400
Offset: 1

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Author

Cino Hilliard, Mar 20 2005

Keywords

Comments

There exists no case in which x or y and z are squares.
Also area A of the right triangles such that A, the sides and the circumradius are integers. - Michel Lagneau, Mar 15 2012

Examples

			x=24, y=7, 24^2 + 7^2 = 25^2. 24 is the 1st entry in the list.
		

Programs

  • PARI
    pythtrisq(n) = { local(a,b,c=0,k,x,y,z,vy,wx,vx,vz,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(z), 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]",") ) }