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.

A121728 Middle side (or long leg) of primitive Pythagorean triangle corresponding to hypotenuse A121727.

Original entry on oeis.org

4, 12, 15, 24, 40, 21, 35, 60, 63, 84, 45, 112, 56, 99, 144, 55, 77, 80, 180, 143, 220, 72, 117, 91, 195, 264, 140, 312, 255, 165, 105, 364, 176, 132, 323, 420, 221, 120, 480, 187, 153, 168, 399, 260, 544, 285
Offset: 1

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Author

Lekraj Beedassy, Aug 17 2006

Keywords

Comments

Complete triple (X,Y,Z), with X>Y>Z, is given by X=A121727(n),Y=a(n),Z=A121729(n).

Crossrefs

Programs

  • Maple
    N:= 100000: # for triples with area <= N
    R:= NULL:
    for n from 1 while (2*n+1)*(n+1)*n <= N do
      for m from n+1 by 2 while (m^2 - n^2)*m*n <= N do
        if igcd(m,n) = 1 then
          R:= R, [m^2-n^2,2*m*n,m^2+n^2,(m^2-n^2)*m*n]
        fi
    od od:
    R:= sort(R, (s,t) -> s[4] < t[4] or (s[4] = t[4] and s[3] < t[3])):
    seq(max(t[1],t[2]),t=R); # Robert Israel, Dec 30 2024

Extensions

a(43)=399 inserted by Ray Chandler, Jun 26 2017