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.

A236673 Exponents of powers of 3 that contain all ten decimal digits.

Original entry on oeis.org

39, 45, 47, 48, 53, 57, 60, 61, 62, 63, 64, 65, 67, 69, 70, 71, 72, 73, 74, 76, 77, 78, 79, 80, 82, 83, 85, 86, 87, 88, 89, 90, 92, 93, 94, 95, 96, 97, 98, 99, 102, 103, 105, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123
Offset: 1

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Author

Derek Orr, Jan 29 2014

Keywords

Comments

It is conjectured that after a(43), a(n) = n + 63 (i.e., natural numbers beginning with 107).
Complement of A236674.

Examples

			3^53 = 19383245667680019896796723, which contains two 1's, two 2's, three 3's, one 4, one 5, five 6's, three 7's, three 8's, four 9's and two 0's, so 53 is in the sequence.
3^57 = 1570042899082081611640534563, which contains four 1's, two 2's, two 3's, three 4's, three 5's, three 6's, one 7, three 8's, two 9's and five 0's.
58 is not in the sequence because there are no 5's in 3^58 = 4710128697246244834921603689.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[0, 200], Union[IntegerDigits[3^#]] == Range[0, 9] &] (* T. D. Noe, Jan 29 2014 *)
  • Python
    def PanDig(x):
      a = '1234567890'
      for n in range(10**3):
        count = 0
        for i in a:
          if str(x**n).count(i) > 0:
            count += 1
          else:
            break
        if count == len(a):
          print(n)