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.

A044956 Numbers with no two equally numerous base 7 digits.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 16, 24, 32, 40, 48, 49, 50, 56, 57, 58, 59, 60, 61, 62, 64, 65, 71, 73, 78, 81, 85, 89, 92, 97, 98, 100, 106, 107, 112, 113, 114, 115, 116, 117, 118, 121, 122, 128, 130, 135, 138, 142, 146, 147, 150, 155, 157, 163, 164
Offset: 1

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Keywords

Examples

			106 in base 7 is 211, which has one more 1 than it has 2's.
107 in base 7 is 212, which has one more 2 than it has 1's.
108 in base 7 is 213. Since each digit occurs as many times as the others (once each), 108 is not in the sequence.
		

Crossrefs

Cf. A007093 (numbers in base 7), A023802.

Programs

  • Mathematica
    enb7Q[n_] := Module[{t = Tally[IntegerDigits[n, 7]][[All, 2]]}, Length[t] == Length[Union[t]]]; Select[Range[200], enb7Q] (* Harvey P. Dale, Jul 26 2018 *)