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The Python source code for generating this image:

from math import log  limit = 400 radius = 17 margin = 4 xscale = yscale = 128 skew = 0.285  def A051037():     yield 1     seq = [1]     spiders = [(2,2,0,0),(3,3,0,1),(5,5,0,2)]     while True:         x,p,i,j = min(spiders)         if x != seq[-1]:             yield x             seq.append(x)         spiders[j] = (p*seq[i+1],p,i+1,j)  def nfactors(h,p):     nf = 0     while h % p == 0:         nf += 1         h //= p     return nf  seq = [] for h in A051037():     if h > limit:         break     seq.append((h,nfactors(h,2),nfactors(h,3),nfactors(h,5)))  leftmost = max([k for h,i,j,k in seq]) rightmost = max([j for h,i,j,k in seq]) leftwidth = int(0.5 + log(5) * leftmost * xscale + radius + margin) rightwidth = int(0.5 + log(3) * rightmost * xscale + radius + margin) width = leftwidth + rightwidth height = int(0.5 + log(limit) * yscale + 2*(radius + margin))  def place(h,i,j,k):     # logical coordinates     x = j * log(3) - k * log(5) + i * skew     y = log(h)          # physical coordinates     x = (x*xscale) + leftwidth     y = (-y*yscale) + height - radius - margin          return (x,y)  print '''<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd"> <svg xmlns="http://www.w3.org/2000/svg" version="1.1" width="%d" height="%d">''' % (width,height)  print '    <g style="fill:none;stroke:#ffaaaa;">'  l = 1 base = 1 while l <= limit:     y = -yscale*log(l) + height - radius - margin     print '        <path d="M0,%0.2fL%d,%0.2f"/>' % (y,width,y)     l += base     if l == 10*base:         base = l  print "    </g>" print '    <g style="fill:none;stroke-width:1.5;stroke:#0000cc;">'  def drawSegment(p,q):     x1,y1=p     x2,y2=q     print '        <path d="M%0.2f,%0.2fL%0.2f,%0.2f"/>' % (x1,y1,x2,y2)  for h,i,j,k in seq:     x,y = place(h,i,j,k)     if i > 0:         drawSegment(place(h//2,i-1,j,k),(x,y))     if j > 0:         drawSegment(place(h//3,i,j-1,k),(x,y))     if k > 0:         drawSegment(place(h//5,i,j,k-1),(x,y))  print "    </g>" print '    <g style="fill:#ffffff;stroke:#000000;">'  for h,i,j,k in seq:     x,y = place(h,i,j,k)     print '        <circle cx="%0.2f" cy="%0.2f" r="%d"/>' % (x,y,radius)  # pairs of first value with size: size of that value fontsizes = {1:33, 5:30, 10:27, 20:24, 100:20, 200:18}  for h,i,j,k in seq:     x,y = place(h,i,j,k)     if h in fontsizes:         print "    </g>"         print '    <g style="font-family:Times;font-size:%d;text-anchor:middle;">' % fontsizes[h]         lower = fontsizes[h] / 3.     print '        <text x="%0.2f" y="%0.2f">%d</text>' %(x,y+lower,h) print "    </g>" print "</svg>" 

• 2007-03-14 05:08 David Eppstein 1363×809×0 (13167 bytes) A [[Hasse diagram]] of [[divisibility]] relationships among [[regular number]]s up to 400. Inspired by similar diagrams in a paper by Kurenniemi [http://www.beige.org/projects/dimi/CSDL2.pdf].