#A208892
#author : Matthijs Coster
#explanation:
#start : start-value
#end : end-value
#diff : difference between start-value and end-value
#maxfac : maximum of different prime-factors (see A002110)
#repeat : number of signatures which corresponds
#dx : efficient chosen number to map signatures onto integers
#u : representation of signature as integer
#n = p1^a1..pk^ak; a1 <= ... <= ak
#u = a1 if k = 1
#u = a1*dx+a2 if k = 2
#u = (a1*dx+a2)*dx+a3 if k = 3 (etc.)
#P is used to produce u
#Q = (u[nn] ... u[nn+diff])
start = 1
end = 1200
repeat = 7
dx = 10
maxfac = 5
diff = end - start
P = vector(ZZ,maxfac)
Q = vector(ZZ,diff+1)
for n in (start..end) :
  u = 0
  f = factor(n)
  l = len(f)
  for i in (0..l-1) :
    g = f[i]
    P[i] = g[1]
  for i in (0..l-1) :
    m = 10
    t = 0
    for j in (0..l-1) :
      if (0 < P[j]) & (P[j] < m) :
        t = j
        m = P[t]
    P[t] = 0
    u = dx*u + m
  Q[n-start] = u
  for k in (repeat..n-start-1) :
    if Q[k] == u :
      OK = true
      for i in (1..repeat-1) :
        if not Q[k-i] == Q[n-start-i] :
          OK = false
      if OK :
        print "solution", start+k-repeat+1, "..", start+k, n-repeat+1, "..", n
print "ready"