Enigmatic Code

Programming Enigma Puzzles

Enigma 1577: Happy New Year

From New Scientist #2742, 9th January 2010 [link]

I have written down three 3-digit numbers which between them use nine different digits. One of the numbers is a perfect square and another is a triangular number. The sum of the three numbers is 2010.

What, in ascending order, are the three numbers?

[enigma1577]

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One response to “Enigma 1577: Happy New Year

  1. Jim Randell 9 February 2012 at 11:14 am

    The following Python program runs in 38ms.

    from enigma import irange, printf
    
    # 3-digit square numbers
    for i in irange(11, 31):
      n = i * i
      d1 = set(str(n))
      if not len(d1) == 3: continue
    
      # 3-digit triangular numbers
      for j in irange(14, 44):
        t = j * (j+1) // 2
        d2 = d1.union(set(str(t)))
        if not len(d2) == 6: continue
    
        # remaining number
        r = 2010 - (n + t)
        if not(99 < r < 1000): continue
        d3 = d2.union(set(str(r)))
        if not len(d3) == 9: continue
        printf("{i}^2 = {n}, T[{j}] = {t}, r = {r}")
    

    Solution: The numbers are: 325, 784 and 901.

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